Science.gov

Sample records for abbot prism chagas

  1. James Abbot McNeill Whistler: "At the Piano."

    ERIC Educational Resources Information Center

    Hallenberg, Heather

    1987-01-01

    "At the Piano," an oil-on-canvas painting completed in 1859 by James Abbot McNeill Whistler, is used as the basis of a lesson designed to help junior high school students analyze the painting's mood, subject matter, and composition. (JDH)

  2. Chagas Disease

    MedlinePlus

    Chagas disease is caused by a parasite. It is common in Latin America but not in the United States. ... nose, the bite wound or a cut. The disease can also spread through contaminated food, a blood ...

  3. Chagas disease

    MedlinePlus

    ... will help control the spread of the disease. Blood banks in Central and South America screen donors for ... discarded if the donor has the parasite. Most blood banks in the United States began screening for Chagas ...

  4. On the occasion of the Charles Greeley Abbot Award by the American Solar Energy Society

    SciTech Connect

    Chandrasekhar, S. )

    1993-09-01

    In 1991 the Charles Greely Abbot Award of the American Solar Energy Society was awarded to Dr. Subrahmanyan Chandrasekhar, in recognition of his well-known work on the internal operation and life cycle of stars such as the sun, and for his development of the new radiation heat transfer and fluid flow analysis techniques he had found to be necessary to do this work. His acceptance address is presented here, which explains the relationship between Abbot's work on the solar constant and Dr. Chandrasekhar's research.

  5. Chagas Disease (American trypanosomiasis)

    MedlinePlus

    ... Features Commentaries 2014 Multimedia Contacts Chagas disease (American trypanosomiasis) Fact sheet Updated March 2016 Key facts About ... is essential. Chagas disease, also known as American trypanosomiasis, is a potentially life-threatening illness caused by ...

  6. Chagas' disease.

    PubMed Central

    Tanowitz, H B; Kirchhoff, L V; Simon, D; Morris, S A; Weiss, L M; Wittner, M

    1992-01-01

    Chagas' disease, caused by Trypanosoma cruzi, is an important cause of morbidity in many countries in Latin America. The important modes of transmission are by the bite of the reduviid bug and blood transfusion. The organism exists in three morphological forms: trypomastigotes, amastigotes, and epimastigotes. The mechanism of transformation and differentiation is currently being explored, and signal transduction pathways of the parasites may be involved in this process. Parasite adherence to and invasion of host cells is a complex process involving complement, phospholipase, penetrin, neuraminidase, and hemolysin. Two clinical forms of the disease are recognized, acute and chronic. During the acute stage pathological damage is related to the presence of the parasite, whereas in the chronic stage few parasites are found. In recent years the roles of tumor necrosis factor, gamma interferon, and the interleukins in the pathogenesis of this infection have been reported. The common manifestations of chronic cardiomyopathy are arrhythmias and thromboembolic events. Autoimmune, neurogenic, and microvascular factors may be important in the pathogenesis of the cardiomyopathy. The gastrointestinal tract is another important target, and "mega syndromes" are common manifestations. The diagnosis and treatment of this infection are active areas of investigation. New serological and molecular biological techniques have improved the diagnosis of chronic infection. Exacerbations of T. cruzi infection have been reported for patients receiving immuno-suppressive therapy and for those with AIDS. Images PMID:1423218

  7. Composite Spectrometer Prisms

    NASA Technical Reports Server (NTRS)

    Breckinridge, J. B.; Page, N. A.; Rodgers, J. M.

    1985-01-01

    Efficient linear dispersive element for spectrometer instruments achieved using several different glasses in multiple-element prism. Good results obtained in both two-and three-element prisms using variety of different glass materials.

  8. Australopithecine enamel prism patterns.

    PubMed

    Vrba, E S; Grine, F E

    1978-11-24

    Following a recent suggestion that tooth enamel prism shape differs within Hominoidea, the teeth of a number of extinct and extant hominoid species were analyzed by scanning electron microscopy. The enamel prism patterns of some gracile and robust australopithecine specimens from Sterkfontein, Swartkrans, and Kromdraai are recorded. The characteristic arrangements of enamel prisms in all modern and extinct hominoid species were found to be essentially similar. The implications of enamel prisms for phylogenetic deduction in Hominoidea are discussed. PMID:102032

  9. [Update Chagas disease].

    PubMed

    Molina, Israel; Salvador, Fernando; Sánchez-Montalvá, Adrián

    2016-02-01

    The constant migration flows have favored the presence of people with Chagas disease in regions traditionally regarded as non-endemic, such as North America, Europe, Asia and Oceania. This has forced both health authorities and professionals to be updated in order to respond to such a demand for assistance. Recent years have led to significant progress in the field of diagnosis and treatment of Chagas disease, one of the most neglected tropical diseases. Recent clinical trials are providing new evidence that makes the management of these patients, a constant challenge for the professionals involved. Innovative diagnostic tools and therapeutic regimens, allow us to face the future of Chagas disease with optimism.

  10. Treatment of Chagas Cardiomyopathy

    PubMed Central

    Botoni, Fernando A.; Ribeiro, Antonio Luiz P.; Marinho, Carolina Coimbra; Lima, Marcia Maria Oliveira; Nunes, Maria do Carmo Pereira; Rocha, Manoel Otávio C.

    2013-01-01

    Chagas' disease (ChD), caused by the protozoa Trypanosoma cruzi (T. cruzi), was discovered and described by the Brazilian physician Carlos Chagas in 1909. After a century of original description, trypanosomiasis still brings much misery to humanity and is classified as a neglected tropical disease prevalent in underdeveloped countries, particularly in South America. It is an increasing worldwide problem due to the number of cases in endemic areas and the migration of infected subjects to more developed regions, mainly North America and Europe. Despite its importance, chronic chagas cardiomyopathy (CCC) pathophysiology is yet poorly understood, and independently of its social, clinical, and epidemiological importance, the therapeutic approach of CCC is still transposed from the knowledge acquired from other cardiomyopathies. Therefore, the objective of this review is to describe the treatment of Chagas cardiomyopathy with emphasis on its peculiarities. PMID:24350293

  11. Carlos Chagas: biographical sketch.

    PubMed

    Moncayo, Alvaro

    2010-01-01

    Carlos Chagas was born on 9 July 1878 in the farm "Bon Retiro" located close to the City of Oliveira in the interior of the State of Minas Gerais, Brazil. He started his medical studies in 1897 at the School of Medicine of Rio de Janeiro. In the late XIX century, the works by Louis Pasteur and Robert Koch induced a change in the medical paradigm with emphasis in experimental demonstrations of the causal link between microbes and disease. During the same years in Germany appeared the pathological concept of disease, linking organic lesions with symptoms. All these innovations were adopted by the reforms of the medical schools in Brazil and influenced the scientific formation of Chagas. Chagas completed his medical studies between 1897 and 1903 and his examinations during these years were always ranked with high grades. Oswaldo Cruz accepted Chagas as a doctoral candidate and directed his thesis on "Hematological studies of Malaria" which was received with honors by the examiners. In 1903 the director appointed Chagas as research assistant at the Institute. In those years, the Institute of Manguinhos, under the direction of Oswaldo Cruz, initiated a process of institutional growth and gathered a distinguished group of Brazilian and foreign scientists. In 1907, he was requested to investigate and control a malaria outbreak in Lassance, Minas Gerais. In this moment Chagas could not have imagined that this field research was the beginning of one of the most notable medical discoveries. Chagas was, at the age of 28, a Research Assistant at the Institute of Manguinhos and was studying a new flagellate parasite isolated from triatomine insects captured in the State of Minas Gerais. Chagas made his discoveries in this order: first the causal agent, then the vector and finally the human cases. These notable discoveries were carried out by Chagas in twenty months. At the age of 33 Chagas had completed his discoveries and published the scientific articles that gave him world

  12. Optical Switch Using Risley Prisms

    DOEpatents

    Sweatt, William C.; Christenson, Todd R.

    2005-02-22

    An optical switch using Risley prisms and rotary microactuators to independently rotate the wedge prisms of each Risley prism pair is disclosed. The optical switch comprises an array of input Risley prism pairs that selectively redirect light beams from a plurality of input ports to an array of output Risley prism pairs that similarly direct the light beams to a plurality of output ports. Each wedge prism of each Risley prism pair can be independently rotated by a variable-reluctance stepping rotary microactuator that is fabricated by a multi-layer LIGA process. Each wedge prism can be formed integral to the annular rotor of the rotary microactuator by a DXRL process.

  13. Optical switch using Risley prisms

    SciTech Connect

    Sweatt, William C.; Christenson, Todd R.

    2003-04-15

    An optical switch using Risley prisms and rotary microactuators to independently rotate the wedge prisms of each Risley prism pair is disclosed. The optical switch comprises an array of input Risley prism pairs that selectively redirect light beams from a plurality of input ports to an array of output Risley prism pairs that similarly direct the light beams to a plurality of output ports. Each wedge prism of each Risley prism pair can be independently rotated by a variable-reluctance stepping rotary microactuator that is fabricated by a multi-layer LIGA process. Each wedge prism can be formed integral to the annular rotor of the rotary microactuator by a DXRL process.

  14. Immunology of Chagas' disease*

    PubMed Central

    1974-01-01

    After reviewing present knowledge of the morphology, multiplication, and transmission of Trypanosoma cruzi, this Memorandum discusses the animal models that may be of value in understanding the immune mechanisms operating in Chagas' disease. The role of both circulating antibody and cell-mediated immunity in protection against the parasite is discussed, together with the possibility that immunopathological mechanisms may be responsible for some of the lesions found in patients with Chagas' disease. The immunodiagnostic methods at present available are also reviewed, and the possibility of producing a vaccine for human use is considered in the light of recent findings in experimental animals. A series of recommendations for further research is included. PMID:4218137

  15. Prism users guide.

    SciTech Connect

    Weirs, V. Gregory

    2012-03-01

    Prism is a ParaView plugin that simultaneously displays simulation data and material model data. This document describes its capabilities and how to use them. A demonstration of Prism is given in the first section. The second section contains more detailed notes on less obvious behavior. The third and fourth sections are specifically for Alegra and CTH users. They tell how to generate the simulation data and SESAME files and how to handle aspects of Prism use particular to each of these codes.

  16. Prism adaptation by mental practice.

    PubMed

    Michel, Carine; Gaveau, Jérémie; Pozzo, Thierry; Papaxanthis, Charalambos

    2013-09-01

    The prediction of our actions and their interaction with the external environment is critical for sensorimotor adaptation. For instance, during prism exposure, which deviates laterally our visual field, we progressively correct movement errors by combining sensory feedback with forward model sensory predictions. However, very often we project our actions to the external environment without physically interacting with it (e.g., mental actions). An intriguing question is whether adaptation will occur if we imagine, instead of executing, an arm movement while wearing prisms. Here, we investigated prism adaptation during mental actions. In the first experiment, participants (n = 54) performed arm pointing movements before and after exposure to the optical device. They were equally divided into six groups according to prism exposure: Prisms-Active, Prisms-Imagery, Prisms-Stationary, Prisms-Stationary-Attention, No Conflict-Prisms-Imagery, No Prisms-Imagery. Adaptation, measured by the difference in pointing errors between pre-test and post-test, occurred only in Prisms-Active and Prisms-Imagery conditions. The second experiment confirmed the results of the first experiment and further showed that sensorimotor adaptation was mainly due to proprioceptive realignment in both Prisms-Active (n = 10) and Prisms-Imagery (n = 10) groups. In both experiments adaptation was greater following actual than imagined pointing movements. The present results are the first demonstration of prism adaptation by mental practice under prism exposure and they are discussed in terms of internal forward models and sensorimotor plasticity.

  17. PRISM Spectrograph Optical Design

    NASA Technical Reports Server (NTRS)

    Chipman, Russell A.

    1995-01-01

    The objective of this contract is to explore optical design concepts for the PRISM spectrograph and produce a preliminary optical design. An exciting optical configuration has been developed which will allow both wavelength bands to be imaged onto the same detector array. At present the optical design is only partially complete because PRISM will require a fairly elaborate optical system to meet its specification for throughput (area*solid angle). The most complex part of the design, the spectrograph camera, is complete, providing proof of principle that a feasible design is attainable. This camera requires 3 aspheric mirrors to fit inside the 20x60 cm cross-section package. A complete design with reduced throughput (1/9th) has been prepared. The design documents the optical configuration concept. A suitable dispersing prism material, CdTe, has been identified for the prism spectrograph, after a comparison of many materials.

  18. Paleomagnetic constraints on rotation within Mount Abbot quadrangle, central Sierra Nevada, California

    USGS Publications Warehouse

    Ross, S.L.

    1988-01-01

    The regional photolineament pattern in Mount Abbot quadrangle in the central Sierra Nevada is sigmoidal in plan view. A paleomagnetic investigation was undertaken to determine if this sigmoidal pattern was formed by kinking of originally straight photolineaments after the rock mass cooled below the blocking temperature. If the inner limb of the kink rotated 40??-60?? clockwise with respect to the outer limbs, then there should be a similar difference in the paleomagnetic declinations between the Florence Lake and Bear Creek areas. The paleomagnetic results indicate a clockwise difference in declination of 13.4????7?? of the Bear Creek area with respect to Florence Lake. Thus the sigmoidal pattern could not have formed entirely by rotation afer cooling below the blocking temperature. It is also possible that the observed declination discrepancy is due to tilting, apparent polar wander, or paleomagnetic dispersion instead of rotation. Data from these sites indicate that although no difference in declination is evident, a reheating event may have occurred which could have removed any rotation from the paleomagnetic record, and that there may have been continuous deformation of the rock mass during the formation of the kinks. -from Author

  19. Chagas disease, France.

    PubMed

    Lescure, François-Xavier; Canestri, Ana; Melliez, Hugues; Jauréguiberry, Stéphane; Develoux, Michel; Dorent, Richard; Guiard-Schmid, Jean-Baptiste; Bonnard, Philippe; Ajana, Faïza; Rolla, Valeria; Carlier, Yves; Gay, Frederick; Elghouzzi, Marie-Hélène; Danis, Martin; Pialoux, Gilles

    2008-04-01

    Chagas disease (CD) is endemic to Latin America; its prevalence is highest in Bolivia. CD is sometimes seen in the United States and Canada among migrants from Latin America, whereas it is rare in Europe. We report 9 cases of imported CD in France from 2004 to 2006.

  20. The anatomy of a hydrothermal (explosion ) breccia, Abbot Village, central Maine

    SciTech Connect

    Roy, D.C. . Dept. of Geology and Geophysics)

    1993-03-01

    An apparently intrusive hydrothermal breccia is exposed in a large outcrop along Kingsbury Stream downstream from the Route 6 bridge in Abbot Village. The breccia intrudes the Siluro-Devonian Madrid Formation which is comprised of thick-bedded metasandstone interbedded with less fine-grained schist and phyllite at regional biotite grade. In the vicinity of the breccia, the bedding attitude in the Madrid is N60E 70SE and the section faces SE. The breccia is a concordant body with respect to bedding and the exposure shows what appears to the SW terminus of the intrusion which extends an unknown distance NE. The main phase of the breccia consists of randomly oriented and angular clasts'' of Madrid metasandstone and schist that are cemented by a quartz-dominated matrix. The random orientation of the clasts is present this phase were it is in contact with the country rock. The matrix comprises about 15% of the volume of the breccia and, in addition to quartz, contains biotite, galena, chalcopyrite ( ), pyrite, and an iron-carbonate. In some interstitial matrix, apparently late iron-carbonate fills post-quartz vugs that contain quartz-crystal terminations. The wall phase contains a higher proportion of biotite schist clasts that in places are bent around each other and metasandstone clasts. Quartz veins extending into the country rock near the breccia follow prominent regional joint directions and suggest hydrofracturing of the Madrid was the principal mechanism for breccia formation. The breccia is interpreted to be of explosive origin with the main phase of the body representing clasts that fell down within the vent'' following upward transport. The wall phase is taken to have formed due to adhesion to the wall of breccia clasts during the eruptive stage.

  1. PRISM project optical instrument

    NASA Technical Reports Server (NTRS)

    Taylor, Charles R.

    1994-01-01

    The scientific goal of the Passively-cooled Reconnaissance of the InterStellar Medium (PRISM) project is to map the emission of molecular hydrogen at 17.035 micrometers and 28.221 micrometers. Since the atmosphere is opaque at these infrared wavelengths, an orbiting telescope is being studied. The availability of infrared focal plane arrays enables infrared imaging spectroscopy at the molecular hydrogen wavelengths. The array proposed for PRISM is 128 pixels square, with a pixel size of 75 micrometers. In order to map the sky in a period of six months, and to resolve the nearer molecular clouds, each pixel must cover 0.5 arcminutes. This sets the focal length at 51.6 cm. In order for the pixel size to be half the diameter of the central diffraction peak at 28 micrometers would require a telescope aperture of 24 cm; an aperture of 60 cm has been selected for the PRISM study for greater light gathering power.

  2. Less-expensive Rochon prisms

    NASA Technical Reports Server (NTRS)

    Ammann, E. O.; Massey, G. A.

    1970-01-01

    Inexpensive Rochon prisms can be produced by substituting easily polished glass for one-half of the calcite. Reciprocal polarizing properties of a conventional Rochon prism are retained, and angular separation between ordinary and extraordinary rays is the same as in all-calcite prism.

  3. Acoustic dispersive prism

    PubMed Central

    Esfahlani, Hussein; Karkar, Sami; Lissek, Herve; Mosig, Juan R.

    2016-01-01

    The optical dispersive prism is a well-studied element, which allows separating white light into its constituent spectral colors, and stands in nature as water droplets. In analogy to this definition, the acoustic dispersive prism should be an acoustic device with capability of splitting a broadband acoustic wave into its constituent Fourier components. However, due to the acoustical nature of materials as well as the design and fabrication difficulties, there is neither any natural acoustic counterpart of the optical prism, nor any artificial design reported so far exhibiting an equivalent acoustic behaviour. Here, based on exotic properties of the acoustic transmission-line metamaterials and exploiting unique physical behaviour of acoustic leaky-wave radiation, we report the first acoustic dispersive prism, effective within the audible frequency range 800 Hz–1300 Hz. The dispersive nature, and consequently the frequency-dependent refractive index of the metamaterial are exploited to split the sound waves towards different and frequency-dependent directions. Meanwhile, the leaky-wave nature of the structure facilitates the sound wave radiation into the ambient medium. PMID:26739504

  4. Prism Adaptation in Schizophrenia

    ERIC Educational Resources Information Center

    Bigelow, Nirav O.; Turner, Beth M.; Andreasen, Nancy C.; Paulsen, Jane S.; O'Leary, Daniel S.; Ho, Beng-Choon

    2006-01-01

    The prism adaptation test examines procedural learning (PL) in which performance facilitation occurs with practice on tasks without the need for conscious awareness. Dynamic interactions between frontostriatal cortices, basal ganglia, and the cerebellum have been shown to play key roles in PL. Disruptions within these neural networks have also…

  5. Generalization of Prism Adaptation

    ERIC Educational Resources Information Center

    Redding, Gordon M.; Wallace, Benjamin

    2006-01-01

    Prism exposure produces 2 kinds of adaptive response. Recalibration is ordinary strategic remapping of spatially coded movement commands to rapidly reduce performance error. Realignment is the extraordinary process of transforming spatial maps to bring the origins of coordinate systems into correspondence. Realignment occurs when spatial…

  6. Reflection by Porro Prisms

    NASA Astrophysics Data System (ADS)

    Greenslade, Thomas B.

    2010-04-01

    Students all know that reflection from a plane mirror produces an image that is reversed right to left and so cannot be read by anyone but Leonardo da Vinci, who kept his notes in mirror writing. A useful counter-example is the Porro prism, which produces an image that is not reversed.

  7. Bathymetry Beneath Abbot Ice Shelf, West Antarctica, From Inversion Of Icebridge Gravity Data: Glaciological And Tectonic Implications

    NASA Astrophysics Data System (ADS)

    Cochran, J. R.; Tinto, K. J.; Bell, R. E.

    2012-12-01

    The Abbot Ice Shelf, with a surface area of just over 30,000 km2, extends for about 400 km along the Eights Coast of West Antarctica between 103°W and 89°W. Thurston Island forms the seaward side of the western portion of the ice shelf, while the eastern portion opens onto the Bellingshausen Sea. The very western edge of the ice shelf opens into the Amundsen Embayment. Operation IceBridge radar data show that the ice thickness over most of the ice shelf varies from 180-350 m. Numerous islands and ice rises imply a complex bathymetry beneath the ice shelf. NASA's Operation IceBridge obtained ten north-south low-altitude airborne geophysical profiles across Abbot Ice Shelf and an east-west line along the ice shelf during the 2009 OIB Antarctic campaign. We inverted the gravity data from these flights to obtain the bathymetry and water cavity geometry on a set of cross sections. Coincident radar data provided control on ice thickness and the location of the bed in grounded regions. The inversion shows that the ice shelf is underlain by a series of east-west trending, apparently fault-bounded, basins. The individual basins are less than 75 km long and vary from 15 to 35 km wide. The ice shelf is pinned on the rift shoulders and intra-rift highs, which results in low (50-150 m/yr) flow rates compared to other ice shelves. The basins do not extend the entire length of the ice shelf but are discontinuous or offset along accommodation zones. This complex geometry may inhibits circulation in the water cavity beneath the ice shelf and contribute to its stability. The structure beneath the Abbot Ice Shelf indicates minor crustal extension. The extension may be related to Latest Cretaceous intra-plate deformation or the presence of a distributed southern plate boundary of the Bellingshausen microplate that is thought to have been active from about 79 Ma to 61 Ma.

  8. The history of Chagas disease.

    PubMed

    Steverding, Dietmar

    2014-01-01

    The ancestor of Trypanosome cruzi was probably introduced to South American via bats approximately 7-10 million years ago. When the first humans arrived in the New World, a sylvatic cycle of Chagas disease was then already well established. Paleoparasitological data suggests that human American trypanosomiasis originated in the Andean area when people founded the first settlements in the coastal region of the Atacama Desert. Identification of T. cruzi as the etiological agent and triatome bugs as the transmission vector of Chagas disease occurred within a few years at the beginning of the 20th century. History also teaches us that human activity leading to environmental changes, in particular deforestation, is the main cause for the spread of Chagas disease. Recently, migration of T. cruzi-infected patients has led to a distribution of Chagas disease from Latin America to non-endemic countries in Europe, North America and western Pacific region. PMID:25011546

  9. The history of Chagas disease

    PubMed Central

    2014-01-01

    The ancestor of Trypanosome cruzi was probably introduced to South American via bats approximately 7-10 million years ago. When the first humans arrived in the New World, a sylvatic cycle of Chagas disease was then already well established. Paleoparasitological data suggests that human American trypanosomiasis originated in the Andean area when people founded the first settlements in the coastal region of the Atacama Desert. Identification of T. cruzi as the etiological agent and triatome bugs as the transmission vector of Chagas disease occurred within a few years at the beginning of the 20th century. History also teaches us that human activity leading to environmental changes, in particular deforestation, is the main cause for the spread of Chagas disease. Recently, migration of T. cruzi-infected patients has led to a distribution of Chagas disease from Latin America to non-endemic countries in Europe, North America and western Pacific region. PMID:25011546

  10. Compound prism design principles, II: triplet and Janssen prisms.

    PubMed

    Hagen, Nathan; Tkaczyk, Tomasz S

    2011-09-01

    Continuing the work of the first paper in this series [Appl. Opt. 50, 4998-5011 (2011)], we extend our design methods to compound prisms composed of three independent elements. The increased degrees of freedom of these asymmetric prisms allow designers to achieve greatly improved dispersion linearity. They also, however, require a more careful tailoring of the merit function to achieve design targets, and so we present several new operands for manipulating the compound prisms' design algorithm. We show that with asymmetric triplet prisms, one can linearize the angular dispersion such that the spectral sampling rate varies by no more than 4% across the entire visible spectral range. Doing this, however, requires large prisms and causes beam compression. By adding a beam compression penalty to the merit function, we show that one can compromise between dispersion linearity and beam compression in order to produce practical systems. For prisms that do not deviate the beam, we show that Janssen prisms provide a form that maintains the degrees of freedom of the triplet and that are capable of up to 32° of dispersion across the visible spectral range. Finally, in order to showcase some of the design flexibility of three-element prisms, we also show how to design for higher-order spectral dispersion to create a two-dimensional spectrum.

  11. Through a prism darkly: re-evaluating prisms and neglect.

    PubMed

    Striemer, Christopher L; Danckert, James A

    2010-07-01

    Many studies have demonstrated that prism adaptation can reduce several symptoms of visual neglect: a disorder in which patients fail to respond to information in contralesional space. The dominant framework to explain these effects proposes that prisms influence higher order visuospatial processes by acting on brain circuits that control spatial attention and perception. However, studies that have directly examined the influence of prisms on perceptual biases inherent to neglect have revealed very few beneficial effects. We propose an alternative explanation whereby many of the beneficial effects of prisms arise via the influence of adaptation on circuits in the dorsal visual stream controlling attention and visuomotor behaviors. We further argue that prisms have little influence on the pervasive perceptual biases that characterize neglect.

  12. Multibeam collimator uses prism stack

    NASA Technical Reports Server (NTRS)

    Minott, P. O.

    1981-01-01

    Optical instrument creates many divergent light beams for surveying and machine element alignment applications. Angles and refractive indices of stack of prisms are selected to divert incoming laser beam by small increments, different for each prism. Angles of emerging beams thus differ by small, precisely-controlled amounts. Instrument is nearly immune to vibration, changes in gravitational force, temperature variations, and mechanical distortion.

  13. Acute Chagas Disease in a Returning Traveler

    PubMed Central

    Carter, Yvonne L.; Juliano, Jonathan J.; Montgomery, Susan P.; Qvarnstrom, Yvonne

    2012-01-01

    Acute Chagas disease is rarely recognized, and the risk for acquiring the disease is undefined in travelers to Central America. We describe a case of acute Chagas disease in a traveler to Costa Rica and highlight the need for increased awareness of this infection in travelers to Chagas-endemic areas. PMID:23091192

  14. Chagas Heart Disease: An Update.

    PubMed

    Malik, Lindsey H; Singh, Gagan D; Amsterdam, Ezra A

    2015-11-01

    Chagas disease, also known as American trypanosomiasis, results from infection by the protozoan Trypanosoma cruzi, and is a major cause of cardiac disease worldwide. Until recently, Chagas disease was confined to those areas of South and Central America where Trypanosoma cruzi is endemic. With the migration of infected individuals, however, the disease has spread, and it is estimated that 6-7 million people worldwide are infected. In the US alone, more than 7 million people from Trypanosoma cruzi-endemic countries became legal US residents by the turn of the century, resulting in a surge of Chagas disease in this country. According to preliminary estimates, the US now ranks seventh in the Western Hemisphere in number of individuals infected with Trypanosoma cruzi, and the disease has become a major public health concern due to limited awareness in the medical community.

  15. Compound prism design principles, I

    PubMed Central

    Hagen, Nathan; Tkaczyk, Tomasz S.

    2011-01-01

    Prisms have been needlessly neglected as components used in modern optical design. In optical throughput, stray light, flexibility, and in their ability to be used in direct-view geometry, they excel over gratings. Here we show that even their well-known weak dispersion relative to gratings has been overrated by designing doublet and double Amici direct-vision compound prisms that have 14° and 23° of dispersion across the visible spectrum, equivalent to 800 and 1300 lines/mm gratings. By taking advantage of the multiple degrees of freedom available in a compound prism design, we also show prisms whose angular dispersion shows improved linearity in wavelength. In order to achieve these designs, we exploit the well-behaved nature of prism design space to write customized algorithms that optimize directly in the nonlinear design space. Using these algorithms, we showcase a number of prism designs that illustrate a performance and flexibility that goes beyond what has often been considered possible with prisms. PMID:22423145

  16. 21 CFR 886.1660 - Gonioscopic prism.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Gonioscopic prism. 886.1660 Section 886.1660 Food... DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1660 Gonioscopic prism. (a) Identification. A gonioscopic prism is a device that is a prism intended to be placed on the eye to study the anterior...

  17. 21 CFR 886.1660 - Gonioscopic prism.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Gonioscopic prism. 886.1660 Section 886.1660 Food... DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1660 Gonioscopic prism. (a) Identification. A gonioscopic prism is a device that is a prism intended to be placed on the eye to study the anterior...

  18. 21 CFR 886.1660 - Gonioscopic prism.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Gonioscopic prism. 886.1660 Section 886.1660 Food... DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1660 Gonioscopic prism. (a) Identification. A gonioscopic prism is a device that is a prism intended to be placed on the eye to study the anterior...

  19. 21 CFR 886.1660 - Gonioscopic prism.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Gonioscopic prism. 886.1660 Section 886.1660 Food... DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1660 Gonioscopic prism. (a) Identification. A gonioscopic prism is a device that is a prism intended to be placed on the eye to study the anterior...

  20. 21 CFR 886.1660 - Gonioscopic prism.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Gonioscopic prism. 886.1660 Section 886.1660 Food... DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1660 Gonioscopic prism. (a) Identification. A gonioscopic prism is a device that is a prism intended to be placed on the eye to study the anterior...

  1. Prism Window for Optical Alignment

    NASA Technical Reports Server (NTRS)

    Tang, Hong

    2008-01-01

    A prism window has been devised for use, with an autocollimator, in aligning optical components that are (1) required to be oriented parallel to each other and/or at a specified angle of incidence with respect to a common optical path and (2) mounted at different positions along the common optical path. The prism window can also be used to align a single optical component at a specified angle of incidence. Prism windows could be generally useful for orienting optical components in manufacture of optical instruments. "Prism window" denotes an application-specific unit comprising two beam-splitter windows that are bonded together at an angle chosen to obtain the specified angle of incidence.

  2. Prism beamswitch for radio telescopes.

    PubMed

    Payne, J M; Ulich, B L

    1978-12-01

    A dielectric prism and switching mechanism have been constructed for beamswitching a Cassegrain radio telescope. Spatially extended radio sources may be mapped without significant confusion utilizing the sensitivity and stability inherent in the conventional Dicke radiometer.

  3. The PRISM concept

    SciTech Connect

    Circeo, L.J. Jr.; Jacobs, G.K.; Camacho, S.L.; Tixier, J.S.

    1994-09-01

    Contaminated soils and buried wastes represent one of the most widespread and costly remediation problems in the United States and other developed countries around the world. This concept of in situ remediation using a plasma arc torch should be directly applicable to many of the contaminated soil remediation needs described the DOE, EPA, and DoD. Plasma Remediation of In Situ Materials (PRISM) could provide a highly efficient, cost-effective, reliable and controllable technique to selectively melt and vitrify any contaminated/buried volume of soils, materials, or objects at any depth underground. If necessary, it could pinpoint underground objects such as buried drums for selective remediation. Plasma arc technology was developed over 30 years ago by NASA for the US space program to simulate reentry temperatures on heat shields. Only recently has this technology begun to emerge as a commercial tool in several industries such as steelmaking, metallurgy, precious metal recovery, and waste disposal. Conceptually, a plasma torch could be used on the ground surface or lowered to the bottom of a small diameter, cased borehole. By raising and operating the torch at progressively higher levels a column of contaminated material would be vitrified and converted into an environmentally safe, glassy residue, highly resistant to leaching. With proper borehole spacing the vitrified columns could be coalesced together to form a contiguous, homogeneous mass of vitrified material which is environmentally safe and highly resistant to leaching.

  4. Heterologous Infection During Chagas' Disease

    NASA Astrophysics Data System (ADS)

    Sibona, G. J.; Condat, C. A.; Cossi Isasi, S.

    2007-05-01

    Human populations are often infected with more than one parasite strain. This is frequently the case with ChagasŠ disease, which is endemic to large regions of Latin America. In the present work we study the dynamics of the heterologous infection for this disease, using a model for the interaction between the trypanosoma cruzi parasite and the immune system. We find the dependence of the nature of the post-acute stage on the parameters characterizing the inoculated infectious strains.

  5. Duodenogastric reflux in Chagas' disease

    SciTech Connect

    Troncon, L.E.; Rezende Filho, J.; Iazigi, N.

    1988-10-01

    Increased duodenogastric reflux has been recognized as a cause of gastric mucosa damage. The frequent finding of bile-stained gastric juice and a suggested higher frequency of lesions of the gastric mucosa in patients with Chagas' disease, which is characterized by a marked reduction of myenteric neurons, suggest that impairment of intrinsic innervation of the gut might be associated with increased duodenogastric reflux. Duodenogastric bile reflux was quantified after intravenous injection of 99mtechnetium-HIDA, in 18 patients with chronic Chagas' disease, 12 controls, and 7 patients with Billroth II gastrectomy. All but one of the chagasic patients were submitted to upper digestive tract endoscopy. High reflux values (greater than or equal to 10%) were detected both in chagasic patients and in the controls, but the values for both groups were significantly lower (P less than 0.01) than those obtained for Billroth II patients (median: 55.79%; range: 12.58-87.22%). Reflux values tended to be higher in the Chagas' disease group (median: 8.20%; range: 0.0-29.40%) than in the control group (median: 3.20%; range: 0.0-30.64%), with no statistical difference between the two groups (P greater than 0.10). Chronic gastritis was detected by endoscopy in 12 chagasic patients, benign gastric ulcer in 2 patients, and a pool of bile in the stomach in 11 patients. However, neither the occurrence of gastric lesions nor the finding of bile-stained gastric juice was associated with high reflux values after (99mTc)HIDA injection. This study suggests that lesions of the intramural nervous system of the gut in Chagas' disease do not appear to be associated with abnormally increased duodenogastric reflux.

  6. Abbot Ice Shelf, structure of the Amundsen Sea continental margin and the southern boundary of the Bellingshausen Plate seaward of West Antarctica

    PubMed Central

    Cochran, James R; Tinto, Kirsty J; Bell, Robin E

    2015-01-01

    Inversion of NASA Operation IceBridge airborne gravity over the Abbot Ice Shelf in West Antarctica for subice bathymetry defines an extensional terrain made up of east-west trending rift basins formed during the early stages of Antarctica/Zealandia rifting. Extension is minor, as rifting jumped north of Thurston Island early in the rifting process. The Amundsen Sea Embayment continental shelf west of the rifted terrain is underlain by a deeper, more extensive sedimentary basin also formed during rifting between Antarctica and Zealandia. A well-defined boundary zone separates the mildly extended Abbot extensional terrain from the deeper Amundsen Embayment shelf basin. The shelf basin has an extension factor, β, of 1.5–1.7 with 80–100 km of extension occurring across an area now 250 km wide. Following this extension, rifting centered north of the present shelf edge and proceeded to continental rupture. Since then, the Amundsen Embayment continental shelf appears to have been tectonically quiescent and shaped by subsidence, sedimentation, and the advance and retreat of the West Antarctic Ice Sheet. The Bellingshausen Plate was located seaward of the Amundsen Sea margin prior to incorporation into the Antarctic Plate at about 62 Ma. During the latter part of its independent existence, Bellingshausen plate motion had a clockwise rotational component relative to Antarctica producing convergence across the north-south trending Bellingshausen Gravity Anomaly structure at 94°W and compressive deformation on the continental slope between 94°W and 102°W. Farther west, the relative motion was extensional along an east-west trending zone occupied by the Marie Byrd Seamounts. Key Points: Abbot Ice Shelf is underlain by E-W rift basins created at ∼90 Ma Amundsen shelf shaped by subsidence, sedimentation, and passage of the ice sheet Bellingshausen plate boundary is located near the base of continental slope and rise PMID:26709352

  7. Chagas Disease Risk in Texas

    PubMed Central

    Sarkar, Sahotra; Strutz, Stavana E.; Frank, David M.; Rivaldi, Chissa–Louise; Sissel, Blake; Sánchez–Cordero, Victor

    2010-01-01

    Background Chagas disease, caused by Trypanosoma cruzi, remains a serious public health concern in many areas of Latin America, including México. It is also endemic in Texas with an autochthonous canine cycle, abundant vectors (Triatoma species) in many counties, and established domestic and peridomestic cycles which make competent reservoirs available throughout the state. Yet, Chagas disease is not reportable in Texas, blood donor screening is not mandatory, and the serological profiles of human and canine populations remain unknown. The purpose of this analysis was to provide a formal risk assessment, including risk maps, which recommends the removal of these lacunae. Methods and Findings The spatial relative risk of the establishment of autochthonous Chagas disease cycles in Texas was assessed using a five–stage analysis. 1. Ecological risk for Chagas disease was established at a fine spatial resolution using a maximum entropy algorithm that takes as input occurrence points of vectors and environmental layers. The analysis was restricted to triatomine vector species for which new data were generated through field collection and through collation of post–1960 museum records in both México and the United States with sufficiently low georeferenced error to be admissible given the spatial resolution of the analysis (1 arc–minute). The new data extended the distribution of vector species to 10 new Texas counties. The models predicted that Triatoma gerstaeckeri has a large region of contiguous suitable habitat in the southern United States and México, T. lecticularia has a diffuse suitable habitat distribution along both coasts of the same region, and T. sanguisuga has a disjoint suitable habitat distribution along the coasts of the United States. The ecological risk is highest in south Texas. 2. Incidence–based relative risk was computed at the county level using the Bayesian Besag–York–Mollié model and post–1960 T. cruzi incidence data. This risk

  8. Autoimmune Pathogenesis of Chagas Heart Disease

    PubMed Central

    Bonney, Kevin M.; Engman, David M.

    2016-01-01

    Chagas heart disease is an inflammatory cardiomyopathy that develops in approximately one-third of individuals infected with the protozoan parasite Trypanosoma cruzi. Since the discovery of T. cruzi by Carlos Chagas >100 years ago, much has been learned about Chagas disease pathogenesis; however, the outcome of T. cruzi infection is highly variable and difficult to predict. Many mechanisms have been proposed to promote tissue inflammation, but the determinants and the relative importance of each have yet to be fully elucidated. The notion that some factor other than the parasite significantly contributes to the development of myocarditis was hypothesized by the first physician-scientists who noted the conspicuous absence of parasites in the hearts of those who succumbed to Chagas disease. One of these factors—autoimmunity—has been extensively studied for more than half a century. Although questions regarding the functional role of autoimmunity in the pathogenesis of Chagas disease remain unanswered, the development of autoimmune responses during infection clearly occurs in some individuals, and the implications that this autoimmunity may be pathogenic are significant. In this review, we summarize what is known about the pathogenesis of Chagas heart disease and conclude with a view of the future of Chagas disease diagnosis, pathogenesis, therapy, and prevention, emphasizing recent advances in these areas that aid in the management of Chagas disease. PMID:25857229

  9. Rotatable prism for pan and tilt

    NASA Technical Reports Server (NTRS)

    Ball, W. B.

    1980-01-01

    Compact, inexpensive, motor-driven prisms change field of view of TV camera. Camera and prism rotate about lens axis to produce pan effect. Rotating prism around axis parallel to lens produces tilt. Size of drive unit and required clearance are little more than size of camera.

  10. Preserving with Prisms: Producing Nets

    ERIC Educational Resources Information Center

    Prummer, Kathy E.; Amador, Julie M.; Wallin, Abraham J.

    2016-01-01

    Two mathematics teachers in a small rural school decided to create a task that would engage seventh graders. The goal of the real-world activity was to help students develop geometric and spatial reasoning and to support their understanding of volume of rectangular prisms. The impetus for the task came from the teachers' desire to engage students…

  11. The Chronic Gastrointestinal Manifestations of Chagas Disease

    PubMed Central

    Matsuda, Nilce Mitiko; Miller, Steven M.; Evora, Paulo R. Barbosa

    2009-01-01

    Chagas disease is an infectious disease caused by the protozoan Trypanosoma cruzi. The disease mainly affects the nervous system, digestive system and heart. The objective of this review is to revise the literature and summarize the main chronic gastrointestinal manifestations of Chagas disease. The chronic gastrointestinal manifestations of Chagas disease are mainly a result of enteric nervous system impairment caused by T. cruzi infection. The anatomical locations most commonly described to be affected by Chagas disease are salivary glands, esophagus, lower esophageal sphincter, stomach, small intestine, colon, gallbladder and biliary tree. Chagas disease has also been studied in association with Helicobacter pylori infection, interstitial cells of Cajal and the incidence of gastrointestinal cancer. PMID:20037711

  12. Diffractively corrected counter-rotating Risley prisms.

    PubMed

    Nie, Xin; Yang, Hongfang; Xue, Changxi

    2015-12-10

    Using the vector refraction equation and the vector diffraction equation, we obtain the expressions of the direction cosines of the refractive rays for the two wedge prisms, and the direction cosines of the diffractive rays for two wedge grisms, in which diffractive gratings were etched into the prism faces to correct the chromatic aberrations. A mathematical model between the two vector equations is proposed to compare the difference angle chromatic aberrations when the Risley prisms/grisms are rotating at different angles. We conclude that the use of diffractively corrected prisms offers a new method to correct chromatic aberrations in Risley prisms. PMID:26836873

  13. A Liquid Prism for Refractive Index Studies

    NASA Astrophysics Data System (ADS)

    Edmiston, Michael D.

    2001-11-01

    A hollow glass prism filled with liquid becomes a "liquid prism". A simple method for constructing hollow glass prisms is presented. A method is given for a demonstration that uses the liquid prism with a laser or laser pointer so the audience can observe differences in refractive index for various liquids. The demonstration provides a quick and easy determination of the sugar content of soft drinks and juices. The prism makes it easy to determine a numerical value for the refractive index of a liquid.

  14. Diffractively corrected counter-rotating Risley prisms.

    PubMed

    Nie, Xin; Yang, Hongfang; Xue, Changxi

    2015-12-10

    Using the vector refraction equation and the vector diffraction equation, we obtain the expressions of the direction cosines of the refractive rays for the two wedge prisms, and the direction cosines of the diffractive rays for two wedge grisms, in which diffractive gratings were etched into the prism faces to correct the chromatic aberrations. A mathematical model between the two vector equations is proposed to compare the difference angle chromatic aberrations when the Risley prisms/grisms are rotating at different angles. We conclude that the use of diffractively corrected prisms offers a new method to correct chromatic aberrations in Risley prisms.

  15. The Vasculature in Chagas Disease

    PubMed Central

    Prado, Cibele M.; Jelicks, Linda A.; Weiss, Louis M.; Factor, Stephen M.; Tanowitz, Herbert B.; Rossi, Marcos A.

    2013-01-01

    The cardiovascular manifestations of Chagas disease are well known. However, the contribution of the vasculature and specifically the microvasculature has received little attention. This chapter reviews the evidence supporting the notion that alterations in the microvasculature especially in the heart contribute to the pathogenesis of chagasic cardiomyopathy. These data may also be important in understanding the contributions of the microvasculature in the aetiologies of other cardiomyopathies. The role of endothelin-1 and of thromboxane A2 vascular spasm and platelet aggregation is also discussed. Further, these observations may provide target(s) for intervention. PMID:21884888

  16. PRISM Polarimetry of Massive Stars

    NASA Astrophysics Data System (ADS)

    Kerkstra, Brennan; Lomax, Jamie R.; Bjorkman, Karen S.; Bjorkman, Jon Eric; Skiff, Brian; Covey, Kevin R.; Wisniewski, John P.

    2016-01-01

    We present the early results from our long-term, multi-epoch filter polarization survey of massive stars in and around young Galactic clusters. These BVRI polarization data were obtained using the PRISM instrument mounted on the 1.8m Perkins Telescope at Lowell Observatory. We first detail the creation of our new semi-automated polarization data reduction pipeline that we developed to process these data. Next, we present our analysis of the instrumental polarization properties of the PRISM instrument, via observations of polarized and unpolarized standard stars. Finally, we present early results on the total and intrinsic polarization behavior of several isolated, previously suggested classical Be stars, and discuss these results in the context of the larger project.BK acknowledges support from a NSF/REU at the University of Oklahoma. This program was also supported by NSF-AST 11411563, 1412110, and 1412135.

  17. PRISM3/GISS Topographic Reconstruction

    USGS Publications Warehouse

    Sohl, Linda E.; Chandler, Mark A.; Schmunk, Robert B.; Mankoff, Ken; Jonas, Jeffrey A.; Foley, Kevin M.; Dowsett, Harry J.

    2009-01-01

    The PRISM3/GISS topographic reconstruction is one of the global data sets incorporated into a new reconstruction for the mid-Piacenzian warm interval of the Pliocene, at about 3.3 to 3.0 Ma. The PRISM3/GISS topography-gridded data set is a digitization of a graphical reconstruction, provided at 2 deg x 2 deg resolution and based on updated paleoaltimetry data and a refined land/ocean mask. Mid-Piacenzian topography as shown in this data set is generally quite similar to modern topography, with three notable differences: (1) the coastline as shown is 25 meters higher than modern sea level, reflecting the hypothesized reduction in ice sheet volume; (2) Hudson Bay is filled in to low elevation, in the absence of evidence for submergence at that time; and (3) the West Antarctic ice sheet is absent, permitting open seaways to exist in Ellsworth and Marie Byrd Lands. Two alternate ice sheet configurations with corresponding vegetation schemes are available; one is a minor modification of the PRISM2 ice reconstruction, and one is derived from the British Antarctic Survey Ice Sheet Model (BAS ISM).

  18. Chagas' disease as a foodborne illness.

    PubMed

    Pereira, Karen Signori; Schmidt, Flávio Luis; Guaraldo, Ana M A; Franco, Regina M B; Dias, Viviane L; Passos, Luiz A C

    2009-02-01

    Various researchers have studied the importance of the oral transmission of Chagas' disease since the mid-20th century. Only in recent years, due to an outbreak that occurred in the Brazilian State of Santa Catarina in 2005 and to various outbreaks occurring during the last 3 years in the Brazilian Amazon basin, mainly associated with the consumption of Amazonian palm berry or açaí (Euterpe oleracea Mart.) juice, has this transmission route aroused the attention of researchers. Nevertheless, reports published in the 1960s already indicated the possibility of Chagas' disease transmission via food in Brazil, mainly in the Amazonian region. Recently, in December 2007, an outbreak of Chagas' disease occurred in Caracas, Venezuela, related to ingestion of contaminated fruit juices. The objective of this article is to point out the importance of foodborne transmission in the etiology of Chagas' disease, on the basis of published research and Brazilian epidemiology data.

  19. Chaga mushroom-induced oxalate nephropathy.

    PubMed

    Kikuchi, Yuko; Seta, Koichi; Ogawa, Yayoi; Takayama, Tatsuya; Nagata, Masao; Taguchi, Takashi; Yahata, Kensei

    2014-06-01

    Chaga mushrooms have been used in folk and botanical medicine as a remedy for cancer, gastritis, ulcers, and tuberculosis of the bones. A 72-year-old Japanese female had been diagnosed with liver cancer 1 year prior to presenting at our department. She underwent hepatectomy of the left lobe 3 months later. Chaga mushroom powder (4 - 5 teaspoons per day) had been ingested for the past 6 months for liver cancer. Renal function decreased and hemodialysis was initiated. Renal biopsy specimens showed diffuse tubular atrophy and interstitial fibrosis. Oxalate crystals were detected in the tubular lumina and urinary sediment and oxalate nephropathy was diagnosed. Chaga mushrooms contain extremely high oxalate concentrations. This is the first report of a case of oxalate nephropathy associated with ingestion of Chaga mushrooms.

  20. Chagas Heart Disease: Report on Recent Developments

    PubMed Central

    Machado, Fabiana S.; Jelicks, Linda A.; Kirchhoff, Louis V.; Shirani, Jamshid; Nagajyothi, Fnu; Mukherjee, Shankar; Nelson, Randin; Coyle, Christina M.; Spray, David C.; Campos de Carvalho, Antonio C.; Guan, Fangxia; Prado, Cibele M.; Lisanti, Michael P.; Weiss, Louis M.; Montgomery, Susan P.; Tanowitz, Herbert B.

    2011-01-01

    Chagas disease, caused by the parasite Trypanosoma cruzi, is an important cause of cardiac disease in endemic areas of Latin America. It is now being diagnosed in non-endemic areas due to immigration. Typical cardiac manifestations of Chagas disease include dilated cardiomyopathy, congestive heart failure, arrhythmias, cardioembolism and stroke. Clinical and laboratory-based research to define the pathology resulting from T. cruzi infection has shed light on many of the cellular and molecular mechanisms leading to these manifestations. Antiparasitic treatment may not be appropriate for patients with advanced cardiac disease. Clinical management of Chagas heart disease is similar to that used for cardiomyopathies due to other processes. Cardiac transplantation has been successfully performed in a small number of patients with Chagas heart disease. PMID:22293860

  1. Inverse solutions for tilting orthogonal double prisms.

    PubMed

    Li, Anhu; Ding, Ye; Bian, Yongming; Liu, Liren

    2014-06-10

    An analytical reverse solution and actual examples are given to show how to direct a laser beam from a pair of orthogonal prisms to given targets in free space. Considering the influences of double-prism structural parameters, a lookup table method to seek the numerical reverse solution of each prism's tilting angle is also proposed for steering the double-prism orientation to track a target position located in the near field. Some case studies, as well as a specified elliptical target trajectory scanned by the cam-based driving double prisms, exhibit the significant application values of the theoretical derivation. The analytic reverse and numerical solutions can be generalized to investigate the synthesis of scanning patterns and the controlling strategy of double-prism tilting motion, the potentials of which can be explored to perform the orientation and position tracking functions in applications of precision engineering fields.

  2. Test procedure for prism compression testing

    SciTech Connect

    Not Available

    1992-05-26

    This procedure describes the setup and procedure for testing hollow clay tile (HCT) masonry prisms. The prism test is the standard engineering test used to determine values for f'{sub m} (specified compressive strength at 28 days) which are then used to obtain Code design allowable values. The prism compression test described herein produces load vs. deflection data which can be used to determine various properties such as the compressive strength, Modulus of Elasticity, and Poisson's ratio. The test prisms are obtained either by extraction from an existing wall or by fabrication using new materials. Prisms obtained from existing walls are fragile and tedious to extract and handle, but are very important because they provide data on the properties of existing walls. Laboratory-built prisms, used to supplement the in-situ prism test data, are easier to obtain, and allow for better control of the prism. Tests are to be made on prism specimens in two directions with respect to the cores: normal and parallel to the cores. Typically, in the Y-12 Plant buildings that have the HCT infill walls, the walls are constructed such that the cores in the HCT units run horizontally. Loading normal to the cores simulates vertical loading (gravity and vertical earthquake motions) on the walls, and loading parallel to the cores simulates the earthquake forces applied to a building wall in the horizontal direction. Prisms of single wythe 8-in. walls and the composite wythe 13-in. walls will be tested. A special Test Fixture (frame) has been designed and built to perform the in-house testing of prisms. Special handling fixtures have been designed to protect the prisms during removal from the wall site and transportation to the Test Fixture. The Test Fixture was designed for approximately a 400 kip allowable load limit.

  3. Test procedure for prism compression testing

    SciTech Connect

    Not Available

    1992-05-26

    This procedure describes the setup and procedure for testing hollow clay tile (HCT) masonry prisms. The prism test is the standard engineering test used to determine values for f`{sub m} (specified compressive strength at 28 days) which are then used to obtain Code design allowable values. The prism compression test described herein produces load vs. deflection data which can be used to determine various properties such as the compressive strength, Modulus of Elasticity, and Poisson`s ratio. The test prisms are obtained either by extraction from an existing wall or by fabrication using new materials. Prisms obtained from existing walls are fragile and tedious to extract and handle, but are very important because they provide data on the properties of existing walls. Laboratory-built prisms, used to supplement the in-situ prism test data, are easier to obtain, and allow for better control of the prism. Tests are to be made on prism specimens in two directions with respect to the cores: normal and parallel to the cores. Typically, in the Y-12 Plant buildings that have the HCT infill walls, the walls are constructed such that the cores in the HCT units run horizontally. Loading normal to the cores simulates vertical loading (gravity and vertical earthquake motions) on the walls, and loading parallel to the cores simulates the earthquake forces applied to a building wall in the horizontal direction. Prisms of single wythe 8-in. walls and the composite wythe 13-in. walls will be tested. A special Test Fixture (frame) has been designed and built to perform the in-house testing of prisms. Special handling fixtures have been designed to protect the prisms during removal from the wall site and transportation to the Test Fixture. The Test Fixture was designed for approximately a 400 kip allowable load limit.

  4. Chagas Disease Cardiomyopathy: Immunopathology and Genetics

    PubMed Central

    Chevillard, Christophe

    2014-01-01

    Chagas disease, caused by the protozoan Trypanosoma cruzi, is endemic in Latin America and affects ca. 10 million people worldwide. About 30% of Chagas disease patients develop chronic Chagas disease cardiomyopathy (CCC), a particularly lethal inflammatory cardiomyopathy that occurs decades after the initial infection, while most patients remain asymptomatic. Mortality rate is higher than that of noninflammatory cardiomyopathy. CCC heart lesions present a Th1 T-cell-rich myocarditis, with cardiomyocyte hypertrophy and prominent fibrosis. Data suggest that the myocarditis plays a major pathogenetic role in disease progression. Major unmet goals include the thorough understanding of disease pathogenesis and therapeutic targets and identification of prognostic genetic factors. Chagas disease thus remains a neglected disease, with no vaccines or antiparasitic drugs proven efficient in chronically infected adults, when most patients are diagnosed. Both familial aggregation of CCC cases and the fact that only 30% of infected patients develop CCC suggest there might be a genetic component to disease susceptibility. Moreover, previous case-control studies have identified some genes associated to human susceptibility to CCC. In this paper, we will review the immunopathogenesis and genetics of Chagas disease, highlighting studies that shed light on the differential progression of Chagas disease patients to CCC. PMID:25210230

  5. Error and adjustment of reflecting prisms

    NASA Astrophysics Data System (ADS)

    Mao, Wenwei

    1997-12-01

    A manufacturing error in the orientation of the working planes of a reflecting prism, such as an angle error or an edge error, will cause the optical axis to deviate and the image to lean. So does an adjustment (position error) of a reflecting prism. A universal method to be used to calculate the optical axis deviation and the image lean caused by the manufacturing error of a reflecting prism is presented. It is suited to all types of reflecting prisms. A means to offset the position error against the manufacturing error of a reflecting prism and the changes of image orientation is discussed. For the calculation to be feasible, a surface named the 'separating surface' is introduced just in front of the real exit face of a real prism. It is the image of the entrance face formed by all reflecting surfaces of the real prism. It can be used to separate the image orientation change caused by the error of the prism's reflecting surfaces from the image orientation change caused by the error of the prism's refracting surface. Based on ray tracing, a set of simple and explicit formulas of the optical axis deviation and the image lean for a general optical wedge is derived.

  6. Carlos Chagas Discoveries as a Drop Back to Scientific Construction of Chronic Chagas Heart Disease.

    PubMed

    Bestetti, Reinaldo B; Restini, Carolina Baraldi A; Couto, Lucélio B

    2016-07-01

    The scientific construction of chronic Chagas heart disease (CCHD) started in 1910 when Carlos Chagas highlighted the presence of cardiac arrhythmia during physical examination of patients with chronic Chagas disease, and described a case of heart failure associated with myocardial inflammation and nests of parasites at autopsy. He described sudden cardiac death associated with arrhythmias in 1911, and its association with complete AV block detected by Jacquet's polygraph as Chagas reported in 1912. Chagas showed the presence of myocardial fibrosis underlying the clinical picture of CCHD in 1916, he presented a full characterization of the clinical aspects of CCHD in 1922. In 1928, Chagas detected fibrosis of the conductive system, and pointed out the presence of marked cardiomegaly at the chest X-Ray associated with minimal symptomatology. The use of serological reaction to diagnose CCHD was put into clinical practice in 1936, after Chagas' death, which along with the 12-lead ECG, revealed the epidemiological importance of CCHD in 1945. In 1953, the long period between initial infection and appearance of CCHD was established, whereas the annual incidence of CCHD from patients with the indeterminate form of the disease was established in 1956. The use of heart catheterization in 1965, exercise stress testing in 1973, Holter monitoring in 1975, Electrophysiologic testing in 1973, echocardiography in 1975, endomyocardial biopsy in 1981, and Magnetic Resonance Imaging in 1995, added to the fundamental clinical aspects of CCHD as described by Carlos Chagas. PMID:27223644

  7. Carlos Chagas Discoveries as a Drop Back to Scientific Construction of Chronic Chagas Heart Disease.

    PubMed

    Bestetti, Reinaldo B; Restini, Carolina Baraldi A; Couto, Lucélio B

    2016-07-01

    The scientific construction of chronic Chagas heart disease (CCHD) started in 1910 when Carlos Chagas highlighted the presence of cardiac arrhythmia during physical examination of patients with chronic Chagas disease, and described a case of heart failure associated with myocardial inflammation and nests of parasites at autopsy. He described sudden cardiac death associated with arrhythmias in 1911, and its association with complete AV block detected by Jacquet's polygraph as Chagas reported in 1912. Chagas showed the presence of myocardial fibrosis underlying the clinical picture of CCHD in 1916, he presented a full characterization of the clinical aspects of CCHD in 1922. In 1928, Chagas detected fibrosis of the conductive system, and pointed out the presence of marked cardiomegaly at the chest X-Ray associated with minimal symptomatology. The use of serological reaction to diagnose CCHD was put into clinical practice in 1936, after Chagas' death, which along with the 12-lead ECG, revealed the epidemiological importance of CCHD in 1945. In 1953, the long period between initial infection and appearance of CCHD was established, whereas the annual incidence of CCHD from patients with the indeterminate form of the disease was established in 1956. The use of heart catheterization in 1965, exercise stress testing in 1973, Holter monitoring in 1975, Electrophysiologic testing in 1973, echocardiography in 1975, endomyocardial biopsy in 1981, and Magnetic Resonance Imaging in 1995, added to the fundamental clinical aspects of CCHD as described by Carlos Chagas.

  8. Carlos Chagas Discoveries as a Drop Back to Scientific Construction of Chronic Chagas Heart Disease

    PubMed Central

    Bestetti, Reinaldo B.; Restini, Carolina Baraldi A.; Couto, Lucélio B.

    2016-01-01

    The scientific construction of chronic Chagas heart disease (CCHD) started in 1910 when Carlos Chagas highlighted the presence of cardiac arrhythmia during physical examination of patients with chronic Chagas disease, and described a case of heart failure associated with myocardial inflammation and nests of parasites at autopsy. He described sudden cardiac death associated with arrhythmias in 1911, and its association with complete AV block detected by Jacquet's polygraph as Chagas reported in 1912. Chagas showed the presence of myocardial fibrosis underlying the clinical picture of CCHD in 1916, he presented a full characterization of the clinical aspects of CCHD in 1922. In 1928, Chagas detected fibrosis of the conductive system, and pointed out the presence of marked cardiomegaly at the chest X-Ray associated with minimal symptomatology. The use of serological reaction to diagnose CCHD was put into clinical practice in 1936, after Chagas' death, which along with the 12-lead ECG, revealed the epidemiological importance of CCHD in 1945. In 1953, the long period between initial infection and appearance of CCHD was established, whereas the annual incidence of CCHD from patients with the indeterminate form of the disease was established in 1956. The use of heart catheterization in 1965, exercise stress testing in 1973, Holter monitoring in 1975, Electrophysiologic testing in 1973, echocardiography in 1975, endomyocardial biopsy in 1981, and Magnetic Resonance Imaging in 1995, added to the fundamental clinical aspects of CCHD as described by Carlos Chagas. PMID:27223644

  9. Abbot Ice Shelf, structure of the Amundsen Sea continental margin and the southern boundary of the Bellingshausen Plate seaward of West Antarctica

    NASA Astrophysics Data System (ADS)

    Cochran, James R.; Tinto, Kirsty J.; Bell, Robin E.

    2015-05-01

    Inversion of NASA Operation IceBridge airborne gravity over the Abbot Ice Shelf in West Antarctica for subice bathymetry defines an extensional terrain made up of east-west trending rift basins formed during the early stages of Antarctica/Zealandia rifting. Extension is minor, as rifting jumped north of Thurston Island early in the rifting process. The Amundsen Sea Embayment continental shelf west of the rifted terrain is underlain by a deeper, more extensive sedimentary basin also formed during rifting between Antarctica and Zealandia. A well-defined boundary zone separates the mildly extended Abbot extensional terrain from the deeper Amundsen Embayment shelf basin. The shelf basin has an extension factor, β, of 1.5-1.7 with 80-100 km of extension occurring across an area now 250 km wide. Following this extension, rifting centered north of the present shelf edge and proceeded to continental rupture. Since then, the Amundsen Embayment continental shelf appears to have been tectonically quiescent and shaped by subsidence, sedimentation, and the advance and retreat of the West Antarctic Ice Sheet. The Bellingshausen Plate was located seaward of the Amundsen Sea margin prior to incorporation into the Antarctic Plate at about 62 Ma. During the latter part of its independent existence, Bellingshausen plate motion had a clockwise rotational component relative to Antarctica producing convergence across the north-south trending Bellingshausen Gravity Anomaly structure at 94°W and compressive deformation on the continental slope between 94°W and 102°W. Farther west, the relative motion was extensional along an east-west trending zone occupied by the Marie Byrd Seamounts. The copyright line for this article was changed on 5 JUN 2015 after original online publication.

  10. American Trypanosomiasis (Also Known as Chagas Disease) Diagnosis

    MedlinePlus

    ... CDC Cancel Submit Search The CDC Parasites - American Trypanosomiasis (also known as Chagas Disease) Note: Javascript is ... see the DPDx Web site: Chagas disease (American Trypanosomiasis) Diagnostic Procedures: Blood Specimens Get Email Updates To ...

  11. American Trypanosomiasis (Also Known as Chagas Disease) Blood Screening FAQs

    MedlinePlus

    ... concerned about getting Chagas disease? Why are blood banks now screening for Chagas disease? The transmission of ... have the disease after all. Will the blood bank let me know if my blood tests positive ...

  12. Immunosuppression and Chagas Disease: A Management Challenge

    PubMed Central

    Pinazo, María-Jesús; Espinosa, Gerard; Cortes-Lletget, Cristina; Posada, Elizabeth de Jesús; Aldasoro, Edelweiss; Oliveira, Inés; Muñoz, Jose; Gállego, Montserrat; Gascon, Joaquim

    2013-01-01

    Immunosuppression, which has become an increasingly relevant clinical condition in the last 50 years, modifies the natural history of Trypanosoma cruzi infection in most patients with Chagas disease. The main goal in this setting is to prevent the consequences of reactivation of T. cruzi infection by close monitoring. We analyze the relationship between Chagas disease and three immunosuppressant conditions, including a description of clinical cases seen at our center, a brief review of the literature, and recommendations for the management of these patients based on our experience and on the data in the literature. T. cruzi infection is considered an opportunistic parasitic infection indicative of AIDS, and clinical manifestations of reactivation are more severe than in acute Chagas disease. Parasitemia is the most important defining feature of reactivation. Treatment with benznidazole and/or nifurtimox is strongly recommended in such cases. It seems reasonable to administer trypanocidal treatment only to asymptomatic immunosuppressed patients with detectable parasitemia, and/or patients with clinically defined reactivation. Specific treatment for Chagas disease does not appear to be related to a higher incidence of neoplasms, and a direct role of T. cruzi in the etiology of neoplastic disease has not been confirmed. Systemic immunosuppressive diseases or immunosuppressants can modify the natural course of T. cruzi infection. Immunosuppressive doses of corticosteroids have not been associated with higher rates of reactivation of Chagas disease. Despite a lack of evidence-based data, treatment with benznidazole or nifurtimox should be initiated before immunosuppression where possible to reduce the risk of reactivation. Timely antiparasitic treatment with benznidazole and nifurtimox (or with posaconazole in cases of therapeutic failure) has proven to be highly effective in preventing Chagas disease reactivation, even if such treatment has not been formally

  13. Chagas Disease and Breast-feeding

    PubMed Central

    López-Vélez, Rogelio

    2013-01-01

    Chagas disease (infection by the protozoan Trypanosoma cruzi) is a major parasitic disease of the Americas and one of the main neglected tropical diseases. Although various routes of transmission sre recognized, the risk for transmission of the infection through breast-feeding has not clearly been established. We reviewed the literature on transmission of T. cruzi through breast-feeding to provide breast-feeding mothers with Chagas disease with medical guidance. Although data from animal studies and human studies are scarce, we do not recommend that mothers with Chagas disease discontinue breast-feeding, unless they are experiencing the acute phase of the disease, reactivated disease resulting from immunosuppression, or bleeding nipples. In these cases, thermal treatment of milk before feeding the infant may be considered. PMID:24050257

  14. Developments in the management of Chagas cardiomyopathy.

    PubMed

    Tanowitz, Herbert B; Machado, Fabiana S; Spray, David C; Friedman, Joel M; Weiss, Oren S; Lora, Jose N; Nagajyothi, Jyothi; Moraes, Diego N; Garg, Nisha Jain; Nunes, Maria Carmo P; Ribeiro, Antonio Luiz P

    2015-12-01

    Over 100 years have elapsed since the discovery of Chagas disease and there is still much to learn regarding pathogenesis and treatment. Although there are antiparasitic drugs available, such as benznidazole and nifurtimox, they are not totally reliable and often toxic. A recently released negative clinical trial with benznidazole in patients with chronic Chagas cardiomyopathy further reinforces the concerns regarding its effectiveness. New drugs and new delivery systems, including those based on nanotechnology, are being sought. Although vaccine development is still in its infancy, the reality of a therapeutic vaccine remains a challenge. New ECG methods may help to recognize patients prone to developing malignant ventricular arrhythmias. The management of heart failure, stroke and arrhythmias also remains a challenge. Although animal experiments have suggested that stem cell based therapy may be therapeutic in the management of heart failure in Chagas cardiomyopathy, clinical trials have not been promising.

  15. Developments in the management of Chagas cardiomyopathy.

    PubMed

    Tanowitz, Herbert B; Machado, Fabiana S; Spray, David C; Friedman, Joel M; Weiss, Oren S; Lora, Jose N; Nagajyothi, Jyothi; Moraes, Diego N; Garg, Nisha Jain; Nunes, Maria Carmo P; Ribeiro, Antonio Luiz P

    2015-12-01

    Over 100 years have elapsed since the discovery of Chagas disease and there is still much to learn regarding pathogenesis and treatment. Although there are antiparasitic drugs available, such as benznidazole and nifurtimox, they are not totally reliable and often toxic. A recently released negative clinical trial with benznidazole in patients with chronic Chagas cardiomyopathy further reinforces the concerns regarding its effectiveness. New drugs and new delivery systems, including those based on nanotechnology, are being sought. Although vaccine development is still in its infancy, the reality of a therapeutic vaccine remains a challenge. New ECG methods may help to recognize patients prone to developing malignant ventricular arrhythmias. The management of heart failure, stroke and arrhythmias also remains a challenge. Although animal experiments have suggested that stem cell based therapy may be therapeutic in the management of heart failure in Chagas cardiomyopathy, clinical trials have not been promising. PMID:26496376

  16. Chagas disease and breast-feeding.

    PubMed

    Norman, Francesca F; López-Vélez, Rogelio

    2013-10-01

    Chagas disease (infection by the protozoan Trypanosoma cruzi) is a major parasitic disease of the Americas and one of the main neglected tropical diseases. Although various routes of transmission sre recognized, the risk for transmission of the infection through breast-feeding has not clearly been established. We reviewed the literature on transmission of T. cruzi through breast-feeding to provide breast-feeding mothers with Chagas disease with medical guidance. Although data from animal studies and human studies are scarce, we do not recommend that mothers with Chagas disease discontinue breast-feeding, unless they are experiencing the acute phase of the disease, reactivated disease resulting from immunosuppression, or bleeding nipples. In these cases, thermal treatment of milk before feeding the infant may be considered.

  17. 21 CFR 886.1650 - Ophthalmic bar prism.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Ophthalmic bar prism. 886.1650 Section 886.1650...) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1650 Ophthalmic bar prism. (a) Identification. An ophthalmic bar prism is a device that is a bar composed of fused prisms of gradually...

  18. 21 CFR 886.1650 - Ophthalmic bar prism.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Ophthalmic bar prism. 886.1650 Section 886.1650...) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1650 Ophthalmic bar prism. (a) Identification. An ophthalmic bar prism is a device that is a bar composed of fused prisms of gradually...

  19. An Easily Constructed Trigonal Prism Model.

    ERIC Educational Resources Information Center

    Yamana, Shukichi

    1984-01-01

    A model of a trigonal prism which is useful for teaching stereochemistry (especially of the neodymium enneahydrate ion), can be made easily by using a sealed, empty envelope. The steps necessary to accomplish this task are presented. (JN)

  20. OPERA: Objective Prism Enhanced Reduction Algorithms

    NASA Astrophysics Data System (ADS)

    Universidad Complutense de Madrid Astrophysics Research Group

    2015-09-01

    OPERA (Objective Prism Enhanced Reduction Algorithms) automatically analyzes astronomical images using the objective-prism (OP) technique to register thousands of low resolution spectra in large areas. It detects objects in an image, extracts one-dimensional spectra, and identifies the emission line feature. The main advantages of this method are: 1) to avoid subjectivity inherent to visual inspection used in past studies; and 2) the ability to obtain physical parameters without follow-up spectroscopy.

  1. Could Carlos Chagas' assumption on the relationship between goiter and chronic Chagas heart disease be correct? A historical reappraisal.

    PubMed

    Bestetti, Reinaldo B; Cardinalli-Neto, Augusto; Restini, Carolina B A; Couto, Lucelio B

    2016-01-01

    In 1910, Chagas divided the clinical manifestations of the chronic form of Chagas disease according to heart, Central Nervous System, and thyroid involvement, particularly the presence of goiter. Chagas emphasized the association of goiter with poor houses infested with kissing bugs, the similarity of the clinical picture with that of patients underwent partial thyroidectomy, and with the presence of thyroid sclerosis (inflammation) on histological examination. In addition, Chagas observed that all people living in poor houses infested by sucking bugs had goiter, contrasting with persons who lived in the same region, drinking the same water, but living in good houses, which did not have goiter. Furthermore, Chagas stressed the fact that people without any evidence of thyroid disease that migrated to live in poor houses in areas infested by sucking bugs developed thyroid disease some time later. Finally, and more importantly, Chagas emphasized the association of goiter with cardiac abnormalities in 80% of patients with chronic Chagas heart disease. Despite this, other authors working in different regions did not confirm such an association. A reappraisal of data from a work published in 1949 clearly shows that the presence of goiter was statistically associated with chronic Chagas heart disease and with chronic Chagas disease. Our paper highlights once more the grandiosity of Chagas' work, which has been proved to be correct even in the history of goiter, and justifies our claim for a posthumous Nobel Prize inasmuch as his work was not perceived by the Karolinska Institute.

  2. Could Carlos Chagas' assumption on the relationship between goiter and chronic Chagas heart disease be correct? A historical reappraisal.

    PubMed

    Bestetti, Reinaldo B; Cardinalli-Neto, Augusto; Restini, Carolina B A; Couto, Lucelio B

    2016-01-01

    In 1910, Chagas divided the clinical manifestations of the chronic form of Chagas disease according to heart, Central Nervous System, and thyroid involvement, particularly the presence of goiter. Chagas emphasized the association of goiter with poor houses infested with kissing bugs, the similarity of the clinical picture with that of patients underwent partial thyroidectomy, and with the presence of thyroid sclerosis (inflammation) on histological examination. In addition, Chagas observed that all people living in poor houses infested by sucking bugs had goiter, contrasting with persons who lived in the same region, drinking the same water, but living in good houses, which did not have goiter. Furthermore, Chagas stressed the fact that people without any evidence of thyroid disease that migrated to live in poor houses in areas infested by sucking bugs developed thyroid disease some time later. Finally, and more importantly, Chagas emphasized the association of goiter with cardiac abnormalities in 80% of patients with chronic Chagas heart disease. Despite this, other authors working in different regions did not confirm such an association. A reappraisal of data from a work published in 1949 clearly shows that the presence of goiter was statistically associated with chronic Chagas heart disease and with chronic Chagas disease. Our paper highlights once more the grandiosity of Chagas' work, which has been proved to be correct even in the history of goiter, and justifies our claim for a posthumous Nobel Prize inasmuch as his work was not perceived by the Karolinska Institute. PMID:26433162

  3. A portable direct view configuration prism spectrometer using a double Amici prism

    NASA Astrophysics Data System (ADS)

    Sun, Lanjun; Zhang, Yanchao; Tian, Zhaoshuo; Ren, Xiuyun; Fu, Shiyou

    2015-10-01

    In this paper, we present a prism spectrometer that exploits a double Amici prism dispersion structure. The system consists of a slit, a collimating lens, a double Amici prism, an imaging lens and a CCD. The incident light enter into slit, and then is paralleled by a collimating lens to the double Amici prism. The double Amici prism is used to realize spectral dispersion. The dispersed light is collected by an imaging lens and image on the photosensitive surface of the CCD. The dispersion resolution is theoretical analyzed from the ray tracing point of view. In addition, the imaging position on CCD element at different wavelength is presented according to nonlinear curve of dispersion. The designed prism spectrometer can obtain a high light throughput and less optical distortion spectrum in the spectral range of 370-700nm. In experiment, we measured the spectral resolution of the designed prism spectrometer at five wavelength used a grating monochromator. The designed in-line, direct view configuration prism spectrometer owns the advantages of high light throughput, less optical distortions, compact structure, small volume and easy operation, which has important role in application of laser spectral measurement especially laser remote sensing spectral detection.

  4. LED light recycling using double prisms

    NASA Astrophysics Data System (ADS)

    Ouyang, George; Li, Kenneth

    2013-09-01

    A novel LED recycling scheme using double prisms is presented. Two identical triangular prisms with square bases, one cross-stacked on top of the other, are tight-fit into a mirrored light tunnel. The whole prism/light tunnel assembly is then mounted on top of a square LED source, whose emitting area is the same as that of the base plane of the said prism/light tunnel assembly. Each prism acts as a tapered-down light guide in one dimension, which selectively retro-reflects high angle light along that direction. The outer light tunnel serves as a mirrored wall that folds back any light that escapes outside the two prisms. For a given collection cone angle, the height of the two prisms is optimized using ASAP, a commercial ray-tracing software. Simulation and experimental results show promise in significantly increasing the brightness of the LED sources within the collection cone. Specifically for a 4x recycling ratio a 70% recycling gain in center illuminance has been achieved (i.e., illuminance measured in the forward direction). This scheme has advantages over previous recycling configurations due to its compactness and ease of mounting. For example, compared to Wavien's spherical reflector approach that has been previously published, the current recycling configuration is much smaller in size because instead of fitting a much larger mirrored reflector on top of the LED source, this time we're using a structure that has the same lateral dimensions as those of the LED source itself. Further improvement is also possible if optimization of various system parameters is carried out.

  5. The PRISM3D paleoenvironmental reconstruction

    USGS Publications Warehouse

    Dowsett, H.; Robinson, M.; Haywood, A.M.; Salzmann, U.; Hill, Daniel; Sohl, L.E.; Chandler, M.; Williams, Mark; Foley, K.; Stoll, D.K.

    2010-01-01

    The Pliocene Research, Interpretation and Synoptic Mapping (PRISM) paleoenvironmental reconstruction is an internally consistent and comprehensive global synthesis of a past interval of relatively warm and stable climate. It is regularly used in model studies that aim to better understand Pliocene climate, to improve model performance in future climate scenarios, and to distinguish model-dependent climate effects. The PRISM reconstruction is constantly evolving in order to incorporate additional geographic sites and environmental parameters, and is continuously refined by independent research findings. The new PRISM three dimensional (3D) reconstruction differs from previous PRISM reconstructions in that it includes a subsurface ocean temperature reconstruction, integrates geochemical sea surface temperature proxies to supplement the faunal-based temperature estimates, and uses numerical models for the first time to augment fossil data. Here we describe the components of PRISM3D and describe new findings specific to the new reconstruction. Highlights of the new PRISM3D reconstruction include removal of Hudson Bay and the Great Lakes and creation of open waterways in locations where the current bedrock elevation is less than 25m above modern sea level, due to the removal of the West Antarctic Ice Sheet and the reduction of the East Antarctic Ice Sheet. The mid-Piacenzian oceans were characterized by a reduced east-west temperature gradient in the equatorial Pacific, but PRISM3D data do not imply permanent El Niño conditions. The reduced equator-to-pole temperature gradient that characterized previous PRISM reconstructions is supported by significant displacement of vegetation belts toward the poles, is extended into the Arctic Ocean, and is confirmed by multiple proxies in PRISM3D. Arctic warmth coupled with increased dryness suggests the formation of warm and salty paleo North Atlantic Deep Water (NADW) and a more vigorous thermohaline circulation system that may

  6. How to Get the Full Prism Effect.

    PubMed

    Pochopien, Klaudia; Fahle, Manfred

    2015-08-01

    We investigate how the immediate correction effect decreases mispointing under prisms. Subjects performed rhythmic pointing movements under different conditions with horizontally shifting prisms. Even the first (initial) pointing error is much smaller than the prismatic shift, a phenomenon called the immediate correction effect. Knowledge about the structure of the room and of objects in the room obtained before the prisms were worn may limit the amount of the prismatic displacement perceived. We therefore compared the direct prism effect as well as prismatic adaptation with room illumination switched on versus switched off. Our 44 subjects participated in two experiments, with varying amounts of information about room structure available. The results show a direct effect corresponding to the optical power of the prisms in the dark condition, when in addition body position was slightly rotated in direction of the prismatic shift. But even in the dark, a significant immediate correction effect arises with the fixed body position. The largest immediate correction amounting to almost half of optical displacement arose in the standard condition of bright light and fixed body position. PMID:27433319

  7. Natural Chagas Disease in Four Baboons

    PubMed Central

    Williams, Jeff T.; Dick, Edward J.; VandeBerg, John L.; Hubbard, Gene B.

    2010-01-01

    Background Chagas disease is common in Central and South America and the southern United States. The causative agent is Trypanosoma cruzi (T cruzi, Order Kinetoplastida, Family Trypanosomatidae), a kinetoplastid protozoan parasite of humans and other vertebrates. It is a serious public health issue and the leading cause of heart disease and cardiovascular death in Central and South America. In 1984 a colony baboon was discovered to be infected with T cruzi. Methods Since the initial diagnosis was made by microscopic observation of the amastigote forms of T. cruzi in myocardial fibers, T. cruzi amastigotes have been identified in three additional baboons. Results The primary findings were similar in all four baboons and were congestive heart failure with edema of dependent areas, hydrothorax, hydropericardium, and multifocal to diffuse lymphoplasmacytic myocarditis. Conclusions A baboon animal model of Chagas disease could contribute significantly to the development of therapies for the disease in humans. PMID:18671766

  8. PRISM: a general purpose programming system

    SciTech Connect

    Rogers, C.R.; O'Hara, S.A.

    1983-03-01

    This paper describes the development, uses, and features of the general purpose programming system PRISM, which is the foundation for future program development by the Computer Programming Branch and is available to all personnel within the Air Force Human Resources Laboratory (AFHRL). PRISM was designed to meet the need for an efficient and reliable programming tool that could be used like a high-order programming language but still provide the operating system interface and hardware controls of assembly language. It has special features that make it an especially powerful tool for new software development. These features were derived from an extensive analysis of coding sequences in existing library programs, interactions between library programs, and the identification of common programming procedures. PRISM was specifically designed for the development of general purpose programs by the Technical Services Division of AFHRL within the Computer Programming Branch; however, it is also an effective and efficient tool for applications programmers.

  9. Test procedure for prism compression testing of laboratory built prisms. Hollow clay tile wall testing program

    SciTech Connect

    Fricke, K.E.; Butala, M.B.

    1992-04-01

    This procedure describes the fabrication and testing of hollow clay tile (HCT) prisms under laboratory conditions. Objective of the HCT prism compression tests is to determine the compressive strength, Modulus of Elasticity, and Poissons`s ratio of the HCT walls as they exist in the Y-12 plant walls. Load versus displacement behavior, including the maximum load and post-peak deformation characteristics will be obtained. The prism test is the standard test used to determine values for f`{sub m} (specified compressive strength at 28 days) which are then used to obtain Code design allowable values. Reason for using laboratory built prisms is that it is a cumbersome process to remove prism specimens from existing walls, transport them to the test site, and then load them into a testing fixture. The wall prisms would be quite fragile as they come out of the walls, and thus the use of laboratory built prisms will permit the testing of more specimens under better controlled conditions.

  10. Test procedure for prism compression testing of laboratory built prisms. [Hollow clay tile walls

    SciTech Connect

    Fricke, K.E.; Butala, M.B.

    1992-04-01

    This procedure describes the fabrication and testing of hollow clay tile (HCT) prisms under laboratory conditions. Objective of the HCT prism compression tests is to determine the compressive strength, Modulus of Elasticity, and Poissons's ratio of the HCT walls as they exist in the Y-12 plant walls. Load versus displacement behavior, including the maximum load and post-peak deformation characteristics will be obtained. The prism test is the standard test used to determine values for f'{sub m} (specified compressive strength at 28 days) which are then used to obtain Code design allowable values. Reason for using laboratory built prisms is that it is a cumbersome process to remove prism specimens from existing walls, transport them to the test site, and then load them into a testing fixture. The wall prisms would be quite fragile as they come out of the walls, and thus the use of laboratory built prisms will permit the testing of more specimens under better controlled conditions.

  11. The elimination of Chagas' disease from Brazil

    PubMed Central

    MASSAD, E.

    2008-01-01

    SUMMARY On 9 June 2006 the Pan American Health Organization (PAHO) presented the Minister of Health of Brazil with the International Elimination of Transmission of Chagas' Disease Certificate. This act was the culmination of an intensive process that began in 1991 with the Southern Cone Initiative, a joint agreement between the governments of Argentina, Bolivia, Brazil, Chile, Paraguay, Uruguay and Peru, to control Chagas' disease by the elimination of the main vector, Triatoma infestans. This initiative has been highly successful and the prevalence area of the vector diminished rapidly in the last years. As a consequence, the current seroprevalence in children aged between 0 and 5 years is of the order of 10−5, a clear indication that transmission, if it is occurring, is only accidental. In this review I calculate the basic reproduction number, R0, for Chagas' disease and demonstrate that its relatively low value (1·25) explains why vectorial transmission was interrupted relatively easily. In addition, I used a mathematical model to forecast how long the remaining cases of the disease, as well as the additional vertically transmitted cases will last. PMID:18053273

  12. X-ray Interferometer Using Prism Optics

    SciTech Connect

    Suzuki, Yoshio

    2004-05-12

    Two-beam X-ray interferometer using refractive optics has been developed. A prism made of acrylic resin is used as the beam deflector for hard X-ray wavefront dividing interferometer. This configuration is the same as that of the Fresnel's bi-prism interferometer or the Leith-Upatnieks type two-beam holography in visible light region. Therefore, quantitative analysis of the degree of transversal coherence can be performed by measuring the visibility of interference fringes. It is also possible to realize two-beam holographic imaging in hard X-ray regions.

  13. Ultradispersive adaptive prism based on a coherently prepared atomic medium

    SciTech Connect

    Sautenkov, Vladimir A.; Li Hebin; Rostovtsev, Yuri V.; Scully, Marlan O.

    2010-06-15

    We have experimentally demonstrated an ultra-dispersive optical prism made from a coherently driven Rb atomic vapor. The prism possesses spectral angular dispersion that is 6 orders of magnitude higher than that of a prism made of optical glass; such angular dispersion allows one to spatially resolve light beams with different frequencies separated by a few kilohertz. The prism operates near the resonant frequency of atomic vapor and its dispersion is optically controlled by a coherent driving field.

  14. Molecular Epidemiologic Source Tracking of Orally Transmitted Chagas Disease, Venezuela

    PubMed Central

    Segovia, Maikell; Martínez, Clara E.; Messenger, Louisa A.; Nessi, Anaibeth; Londoño, Juan C.; Espinosa, Raul; Martínez, Cinda; Alfredo, Mijares; Bonfante-Cabarcas, Rafael; Lewis, Michael D.; de Noya, Belkisyolé A.; Miles, Michael A.; Llewellyn, Martin S.

    2013-01-01

    Oral outbreaks of Chagas disease are increasingly reported in Latin America. The transitory presence of Trypanosoma cruzi parasites within contaminated foods, and the rapid consumption of those foods, precludes precise identification of outbreak origin. We report source attribution for 2 peri-urban oral outbreaks of Chagas disease in Venezuela via high resolution microsatellite typing. PMID:23768982

  15. Autoimmune pathogenesis of Chagas heart disease: looking back, looking ahead.

    PubMed

    Bonney, Kevin M; Engman, David M

    2015-06-01

    Chagas heart disease is an inflammatory cardiomyopathy that develops in approximately one-third of individuals infected with the protozoan parasite Trypanosoma cruzi. Since the discovery of T. cruzi by Carlos Chagas >100 years ago, much has been learned about Chagas disease pathogenesis; however, the outcome of T. cruzi infection is highly variable and difficult to predict. Many mechanisms have been proposed to promote tissue inflammation, but the determinants and the relative importance of each have yet to be fully elucidated. The notion that some factor other than the parasite significantly contributes to the development of myocarditis was hypothesized by the first physician-scientists who noted the conspicuous absence of parasites in the hearts of those who succumbed to Chagas disease. One of these factors-autoimmunity-has been extensively studied for more than half a century. Although questions regarding the functional role of autoimmunity in the pathogenesis of Chagas disease remain unanswered, the development of autoimmune responses during infection clearly occurs in some individuals, and the implications that this autoimmunity may be pathogenic are significant. In this review, we summarize what is known about the pathogenesis of Chagas heart disease and conclude with a view of the future of Chagas disease diagnosis, pathogenesis, therapy, and prevention, emphasizing recent advances in these areas that aid in the management of Chagas disease.

  16. Magnetic prism alignment system for measuring large-angle strabismus.

    PubMed

    Bishop, John Edward

    2014-02-01

    Prismatic measurement of large-angle strabismus requires the simultaneous use of two or more prisms for neutralization. To facilitate the clinical measurement of large-angle strabismus a new prism system was designed utilizing a flat plate and a ferrous metal surface coupled with prisms containing rare earth magnets implanted in their base and bottom surfaces. PMID:24569000

  17. 21 CFR 886.1655 - Ophthalmic Fresnel prism.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Ophthalmic Fresnel prism. 886.1655 Section 886...) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1655 Ophthalmic Fresnel prism. (a) Identification. An ophthalmic Fresnel prism is a device that is a thin plastic sheet with embossed rulings...

  18. 21 CFR 886.1655 - Ophthalmic Fresnel prism.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Ophthalmic Fresnel prism. 886.1655 Section 886...) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1655 Ophthalmic Fresnel prism. (a) Identification. An ophthalmic Fresnel prism is a device that is a thin plastic sheet with embossed rulings...

  19. Symmetry Breaking Analysis of Prism Adaptation's Latent Aftereffect

    ERIC Educational Resources Information Center

    Frank, Till D.; Blau, Julia J. C.; Turvey, Michael T.

    2012-01-01

    The effect of prism adaptation on movement is typically reduced when the movement at test (prisms off) differs on some dimension from the movement at training (prisms on). Some adaptation is latent, however, and only revealed through further testing in which the movement at training is fully reinstated. Applying a nonlinear attractor dynamic model…

  20. 21 CFR 886.1665 - Ophthalmic rotary prism.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Ophthalmic rotary prism. 886.1665 Section 886.1665...) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1665 Ophthalmic rotary prism. (a) Identification. An ophthalmic rotary prism is a device with various prismatic powers intended to be handheld...

  1. 21 CFR 886.1655 - Ophthalmic Fresnel prism.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Ophthalmic Fresnel prism. 886.1655 Section 886...) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1655 Ophthalmic Fresnel prism. (a) Identification. An ophthalmic Fresnel prism is a device that is a thin plastic sheet with embossed rulings...

  2. 21 CFR 886.5810 - Ophthalmic prism reader.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Ophthalmic prism reader. 886.5810 Section 886.5810...) MEDICAL DEVICES OPHTHALMIC DEVICES Therapeutic Devices § 886.5810 Ophthalmic prism reader. (a) Identification. An ophthalmic prism reader is a device intended for use by a patient who is in a supine...

  3. 21 CFR 886.5810 - Ophthalmic prism reader.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Ophthalmic prism reader. 886.5810 Section 886.5810...) MEDICAL DEVICES OPHTHALMIC DEVICES Therapeutic Devices § 886.5810 Ophthalmic prism reader. (a) Identification. An ophthalmic prism reader is a device intended for use by a patient who is in a supine...

  4. 21 CFR 886.5810 - Ophthalmic prism reader.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Ophthalmic prism reader. 886.5810 Section 886.5810...) MEDICAL DEVICES OPHTHALMIC DEVICES Therapeutic Devices § 886.5810 Ophthalmic prism reader. (a) Identification. An ophthalmic prism reader is a device intended for use by a patient who is in a supine...

  5. 21 CFR 886.1665 - Ophthalmic rotary prism.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Ophthalmic rotary prism. 886.1665 Section 886.1665...) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1665 Ophthalmic rotary prism. (a) Identification. An ophthalmic rotary prism is a device with various prismatic powers intended to be handheld...

  6. 21 CFR 886.1665 - Ophthalmic rotary prism.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Ophthalmic rotary prism. 886.1665 Section 886.1665...) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1665 Ophthalmic rotary prism. (a) Identification. An ophthalmic rotary prism is a device with various prismatic powers intended to be handheld...

  7. 21 CFR 886.1655 - Ophthalmic Fresnel prism.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Ophthalmic Fresnel prism. 886.1655 Section 886...) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1655 Ophthalmic Fresnel prism. (a) Identification. An ophthalmic Fresnel prism is a device that is a thin plastic sheet with embossed rulings...

  8. 21 CFR 886.1665 - Ophthalmic rotary prism.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Ophthalmic rotary prism. 886.1665 Section 886.1665...) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1665 Ophthalmic rotary prism. (a) Identification. An ophthalmic rotary prism is a device with various prismatic powers intended to be handheld...

  9. 21 CFR 886.1655 - Ophthalmic Fresnel prism.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Ophthalmic Fresnel prism. 886.1655 Section 886...) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1655 Ophthalmic Fresnel prism. (a) Identification. An ophthalmic Fresnel prism is a device that is a thin plastic sheet with embossed rulings...

  10. 21 CFR 886.5810 - Ophthalmic prism reader.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Ophthalmic prism reader. 886.5810 Section 886.5810...) MEDICAL DEVICES OPHTHALMIC DEVICES Therapeutic Devices § 886.5810 Ophthalmic prism reader. (a) Identification. An ophthalmic prism reader is a device intended for use by a patient who is in a supine...

  11. 21 CFR 886.5810 - Ophthalmic prism reader.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Ophthalmic prism reader. 886.5810 Section 886.5810...) MEDICAL DEVICES OPHTHALMIC DEVICES Therapeutic Devices § 886.5810 Ophthalmic prism reader. (a) Identification. An ophthalmic prism reader is a device intended for use by a patient who is in a supine...

  12. 21 CFR 886.1665 - Ophthalmic rotary prism.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Ophthalmic rotary prism. 886.1665 Section 886.1665...) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1665 Ophthalmic rotary prism. (a) Identification. An ophthalmic rotary prism is a device with various prismatic powers intended to be handheld...

  13. Magnetic prism alignment system for measuring large-angle strabismus.

    PubMed

    Bishop, John Edward

    2014-02-01

    Prismatic measurement of large-angle strabismus requires the simultaneous use of two or more prisms for neutralization. To facilitate the clinical measurement of large-angle strabismus a new prism system was designed utilizing a flat plate and a ferrous metal surface coupled with prisms containing rare earth magnets implanted in their base and bottom surfaces.

  14. Reflecting Schmidt/Littrow Prism Imaging Spectrometer

    NASA Technical Reports Server (NTRS)

    Breckinridge, J. B.; Page, N. A.; Shack, R. V.; Shannon, R. R.

    1985-01-01

    High resolution achieved with wide field of view. Imaging Spectrometer features off-axis reflecting optics, including reflecting "slit" that also serves as field flattener. Only refracting element is prism. By scanning slit across object or scene and timing out signal, both spectral and spatial information in scene are obtained.

  15. Comparing Volumes of Prisms and Pyramids

    ERIC Educational Resources Information Center

    Vinogradova, Natalya

    2012-01-01

    Students' experience in using formulas for volumes is often limited to substituting numbers into given formulas. An activity presented in this article may help students make connections between the formulas for volumes of prisms and volumes of pyramids. In addition, some interesting facts from number theory arise, demonstrating strong connections…

  16. Dual-prism interferometer for collimation testing

    SciTech Connect

    Hii, King Ung; Kwek, Kuan Hiang

    2009-01-10

    An air-wedge lateral-shear interferometer using two prisms is presented. With a variable shear, the interferometer is suitable for testing collimation of a wide range of beam sizes down to a few millimeters in diameter. No antireflection coatings are necessary. Collimation for a light source with short coherent length is also demonstrated.

  17. Comparing the Volumes of Rectangular Prisms

    ERIC Educational Resources Information Center

    Assuah, Charles K.; Wiest, Lynda R.

    2010-01-01

    Can middle-grades students determine which of two rectangular prisms has a larger volume? Can they do so without using a formula? Geometry, and particularly the concept of volume, is important in many subjects, such as physics and chemistry. Students greatly enhance their mathematics knowledge when they make generalizations and construct arguments…

  18. Prisms Throw Light on Developmental Disorders

    ERIC Educational Resources Information Center

    Brookes, Rebecca L.; Nicolson, Roderick I.; Fawcett, Angela J.

    2007-01-01

    Prism adaptation, in which the participant adapts to prismatic glasses that deflect vision laterally, is a specific test of cerebellar function. Fourteen dyslexic children (mean age 13.5 years); 14 children with developmental coordination disorder (DCD): 6 of whom had comorbid dyslexia; and 12 control children matched for age and IQ underwent…

  19. Behavioral Consultant Application. PRISM Project Technical Report.

    ERIC Educational Resources Information Center

    Smith, Jesse

    This brief paper describes the Peer Coaching Rural In-Service Model (PRISM) Behavioral Consultant (PBC) program, an online tool for teachers that provides advice on handling simple classroom behavior problems. PBC's advice is based on a series of rules and expressions used by the computer program to make inferences and eliminate inappropriate…

  20. High-Power Prismatic Devices for Oblique Peripheral Prisms

    PubMed Central

    Peli, Eli; Bowers, Alex R.; Keeney, Karen; Jung, Jae-Hyun

    2016-01-01

    ABSTRACT Purpose Horizontal peripheral prisms for hemianopia provide field expansion above and below the horizontal meridian; however, there is a vertical gap leaving the central area (important for driving) without expansion. In the oblique design, tilting the bases of both prism segments toward the horizontal meridian moves the field expansion area vertically and centrally (closing the central gap) while the prisms remain in the peripheral location. However, tilting the prisms results also in a reduction of the lateral field expansion. Higher prism powers are needed to counter this effect. Methods We developed, implemented, and tested a series of designs aimed at increasing the prism power to reduce the central gap while maintaining wide lateral expansion. The designs included inserting the peripheral prisms into carrier lenses that included yoked prism in the opposite direction, combination of two Fresnel segments attached at the base and angled to each other (bi-part prisms), and creating Fresnel prism–like segments from nonparallel periscopic mirror pairs (reflective prisms). Results A modest increase in lateral power was achieved with yoked-prism carriers. Bi-part combination of 36Δ Fresnel segments provided high power with some reduction in image quality. Fresnel reflective prism segments have potential for high power with superior optical quality but may be limited in field extent or by interruptions of the expanded field. Extended apical scotomas, even with unilateral fitting, may limit the utility of very high power prisms. The high-power bi-part and reflective prisms enable a wider effective eye scanning range (more than 15 degrees) into the blind hemifield. Conclusions Conventional prisms of powers higher than the available 57Δ are limited by the binocular impact of a wider apical scotoma and a reduced effective eye scanning range to the blind side. The various designs that we developed may overcome these limitations and find use in various other

  1. Self-referenced prism deflection measurement schemes with microradian precision

    SciTech Connect

    Olson, Rebecca; Paul, Justin; Bergeson, Scott; Durfee, Dallin S

    2005-08-01

    We have demonstrated several inexpensive methods that can be used to measure the deflection angles of prisms with microradian precision. The methods are self-referenced, where various reversals are used to achieve absolute measurements without the need of a reference prism or any expensive precision components other than the prisms under test. These techniques are based on laser interferometry and have been used in our laboratory to characterize parallel-plate beam splitters, penta prisms, right-angle prisms, and corner cube reflectors using only components typically available in an optics laboratory.

  2. Respiratory sinus arrhythmia in Chagas disease.

    PubMed

    Neves, Victor Ribeiro; Peltola, Mirja; Huikuri, Heikki; Rocha, Manoel Otávio da Costa; Ribeiro, Antonio Luiz

    2014-10-01

    We applied the respiratory sinus arrhythmia (RSA) quantification algorithm to 24-hour ECG recordings of Chagas disease (ChD) patients with (G1, n=148) and without left ventricular dysfunction (LVD) (G2, n=33), and in control subjects (G0, n=28). Both ChD groups displayed a reduced RSA index; G1=299 (144-812); G2=335 (162-667), p=0.011, which was correlated with vagal indexes of heart rate variability analysis. RSA index is a marker of vagal modulation in ChD patients.

  3. Effects of Prism Eyeglasses on Objective and Subjective Fixation Disparity.

    PubMed

    Schroth, Volkhard; Joos, Roland; Jaschinski, Wolfgang

    2015-01-01

    In optometry of binocular vision, the question may arise whether prisms should be included in eyeglasses to compensate an oculomotor and/or sensory imbalance between the two eyes. The corresponding measures of objective and subjective fixation disparity may be reduced by the prisms, or the adaptability of the binocular vergence system may diminish effects of the prisms over time. This study investigates effects of wearing prisms constantly for about 5 weeks in daily life. Two groups of 12 participants received eyeglasses with prisms having either a base-in direction or a base-out direction with an amount up to 8 prism diopters. Prisms were prescribed based on clinical fixation disparity test plates at 6 m. Two dependent variables were used: (1) subjective fixation disparity was indicated by a perceived offset of dichoptic nonius lines that were superimposed on the fusion stimuli and (2) objective fixation disparity was measured with a video based eye tracker relative to monocular calibration. Stimuli were presented at 6 m and included either central or more peripheral fusion stimuli. Repeated measurements were made without the prisms and with the prisms after about 5 weeks of wearing these prisms. Objective and subjective fixation disparity were correlated, but the type of fusion stimulus and the direction of the required prism may play a role. The prisms did not reduce the fixation disparity to zero, but induced significant changes in fixation disparity with large effect sizes. Participants receiving base-out prisms showed hypothesized effects, which were concurrent in both types of fixation disparity. In participants receiving base-in prisms, the individual effects of subjective and objective effects were negatively correlated: the larger the subjective (sensory) effect, the smaller the objective (motor) effect. This response pattern was related to the vergence adaptability, i.e. the individual fusional vergence reserves.

  4. Effects of Prism Eyeglasses on Objective and Subjective Fixation Disparity.

    PubMed

    Schroth, Volkhard; Joos, Roland; Jaschinski, Wolfgang

    2015-01-01

    In optometry of binocular vision, the question may arise whether prisms should be included in eyeglasses to compensate an oculomotor and/or sensory imbalance between the two eyes. The corresponding measures of objective and subjective fixation disparity may be reduced by the prisms, or the adaptability of the binocular vergence system may diminish effects of the prisms over time. This study investigates effects of wearing prisms constantly for about 5 weeks in daily life. Two groups of 12 participants received eyeglasses with prisms having either a base-in direction or a base-out direction with an amount up to 8 prism diopters. Prisms were prescribed based on clinical fixation disparity test plates at 6 m. Two dependent variables were used: (1) subjective fixation disparity was indicated by a perceived offset of dichoptic nonius lines that were superimposed on the fusion stimuli and (2) objective fixation disparity was measured with a video based eye tracker relative to monocular calibration. Stimuli were presented at 6 m and included either central or more peripheral fusion stimuli. Repeated measurements were made without the prisms and with the prisms after about 5 weeks of wearing these prisms. Objective and subjective fixation disparity were correlated, but the type of fusion stimulus and the direction of the required prism may play a role. The prisms did not reduce the fixation disparity to zero, but induced significant changes in fixation disparity with large effect sizes. Participants receiving base-out prisms showed hypothesized effects, which were concurrent in both types of fixation disparity. In participants receiving base-in prisms, the individual effects of subjective and objective effects were negatively correlated: the larger the subjective (sensory) effect, the smaller the objective (motor) effect. This response pattern was related to the vergence adaptability, i.e. the individual fusional vergence reserves. PMID:26431525

  5. A global systematic review of Chagas disease prevalence among migrants.

    PubMed

    Conners, Erin E; Vinetz, Joseph M; Weeks, John R; Brouwer, Kimberly C

    2016-04-01

    Human migration has been identified as a potential factor for increased Chagas disease risk and has transformed the disease from a Latin American problem to a global one. We conducted a systematic review of the scientific literature between 2004-2014 in order to: summarize recent seroprevalence estimates of Chagas disease among Latin American migrants, in both endemic and non-endemic settings; compare seroprevalence estimates in migrants to countrywide prevalence estimates; and identify risk factors for Chagas disease among migrants. A total of 320 studies were screened and 23 studies were included. We found evidence that the prevalence of Chagas disease is higher than expected in some migrant groups and that reliance on blood donor screening prevalence estimates underestimates the burden of disease. Overall there is a dearth of high quality epidemiologic studies on the prevalence of Chagas disease in migrants, especially among intra-regional migrants within Latin America. Given that this zoonotic disease cannot likely be eradicated, improved surveillance and reporting is vital to continuing control efforts. More accurate health surveillance of both Latin American migrants and the Chagas disease burden will help countries appropriately scale up their response to this chronic disease. Overall, improved estimates of Chagas disease among migrants would likely serve to highlight the real need for better screening, diagnostics, and treatment of individuals living with the disease.

  6. PRISM3 DOT1 Atlantic Basin Reconstruction

    USGS Publications Warehouse

    Dowsett, Harry; Robinson, Marci; Dwyer, Gary; Chandler, Mark; Cronin, Thomas

    2006-01-01

    PRISM3 DOT1 (Pliocene Research, Interpretation and Synoptic Mapping 3, Deep Ocean Temperature 1) provides a three-dimensional temperature reconstruction for the mid-Pliocene Atlantic basin, the first of several regional data sets that will comprise a global mid-Pliocene reconstruction. DOT1 is an alteration of modern temperature values for the Atlantic Ocean in 4 degree x 5 degree cells in 13 depth layers for December 1 based on Mg/Ca-derived BWT estimates from seventeen DSDP and ODP Sites and SST estimates from the PRISM2 reconstruction (Dowsett et al., 1999). DOT1 reflects a vaguely modern circulation system, assuming similar processes of deep-water formation; however, North Atlantic Deep Water (NADW) production is increased, and Antarctic Bottom Water (AABW) production is decreased. Pliocene NADW was approximately 2 degreesC warmer than modern temperatures, and Pliocene AABW was approximately 0.3 degreesC warmer than modern temperatures.

  7. Use of a Novel Chagas Urine Nanoparticle Test (Chunap) for Diagnosis of Congenital Chagas Disease

    PubMed Central

    Castro-Sesquen, Yagahira E.; Gilman, Robert H.; Galdos-Cardenas, Gerson; Ferrufino, Lisbeth; Sánchez, Gerardo; Valencia Ayala, Edward; Liotta, Lance; Bern, Caryn; Luchini, Alessandra

    2014-01-01

    Background Detection of congenital T. cruzi transmission is considered one of the pillars of control programs of Chagas disease. Congenital transmission accounts for 25% of new infections with an estimated 15,000 infected infants per year. Current programs to detect congenital Chagas disease in Latin America utilize microscopy early in life and serology after 6 months. These programs suffer from low sensitivity by microscopy and high loss to follow-up later in infancy. We developed a Chagas urine nanoparticle test (Chunap) to concentrate, preserve and detect T. cruzi antigens in urine for early, non-invasive diagnosis of congenital Chagas disease. Methodology/Principal Findings This is a proof-of-concept study of Chunap for the early diagnosis of congenital Chagas disease. Poly N-isopropylacrylamide nano-particles functionalized with trypan blue were synthesized by precipitation polymerization and characterized with photon correlation spectroscopy. We evaluated the ability of the nanoparticles to capture, concentrate and preserve T. cruzi antigens. Urine samples from congenitally infected and uninfected infants were then concentrated using these nanoparticles. The antigens were eluted and detected by Western Blot using a monoclonal antibody against T. cruzi lipophosphoglycan. The nanoparticles concentrate T. cruzi antigens by 100 fold (western blot detection limit decreased from 50 ng/ml to 0.5 ng/ml). The sensitivity of Chunap in a single specimen at one month of age was 91.3% (21/23, 95% CI: 71.92%–98.68%), comparable to PCR in two specimens at 0 and 1 month (91.3%) and significantly higher than microscopy in two specimens (34.8%, 95% CI: 16.42%–57.26%). Chunap specificity was 96.5% (71/74 endemic, 12/12 non-endemic specimens). Particle-sequestered T. cruzi antigens were protected from trypsin digestion. Conclusion/Significance Chunap has the potential to be developed into a simple and sensitive test for the early diagnosis of congenital Chagas disease. PMID

  8. Refractive index measurement by prism autocollimation

    NASA Astrophysics Data System (ADS)

    Cheng, Chao-Chia

    2014-03-01

    An autocollimation-based method for measuring the refractive indices of solid or liquids using a Littrow prism is presented. Measurement accuracy is enhanced by use of a telescope. In solids, the refractive index is accurate to three decimal places. Similar accuracy is obtained in liquids by correcting for the wedge angle of the liquid container window. The proposed prismatic method confers high accuracy, compactness, and automation. It is suitable for index measurement applications in undergraduate laboratories.

  9. Chagas disease and globalization of the Amazon.

    PubMed

    Briceño-León, Roberto

    2007-01-01

    The increasing number of autochthonous cases of Chagas disease in the Amazon since the 1970s has led to fear that the disease may become a new public health problem in the region. This transformation in the disease's epidemiological pattern in the Amazon can be explained by environmental and social changes in the last 30 years. The current article draws on the sociological theory of perverse effects to explain these changes as the unwanted result of the shift from the "inward" development model prevailing until the 1970s to the "outward" model that we know as globalization, oriented by industrial forces and international trade. The current article highlights the implementation of five new patterns in agriculture, cattle-raising, mining, lumbering, and urban occupation that have generated changes in the environment and the traditional indigenous habitat and have led to migratory flows, deforestation, sedentary living, the presence of domestic animals, and changes in the habitat that facilitate colonization of human dwellings by vectors and the domestic and work-related transmission of the disease. The expansion of Chagas disease is thus a perverse effect of the globalization process in the Amazon.

  10. Chagas' Disease: Pregnancy and Congenital Transmission

    PubMed Central

    Hernández, Roberto

    2014-01-01

    Chagas disease is a chronic infection that kills approximately 12,000 people a year. Mass migration of chronically infected and asymptomatic persons has caused globalization of Chagas disease and has made nonvectorial infection, including vertical and blood-borne transmission, more of a threat to human communities than vectorial infection. To control transmission, it is essential to test all pregnant women living in endemic countries and all pregnant women having migrated from, or having lived in, endemic countries. All children born to seropositive mothers should be tested not only within the first month of life but also at ~6 months and ~12 months of age. The diagnosis is made by identification of the parasite in blood before the age of 6 months and by identification of the parasite in blood and/or positive serology after 10 months of age. Follow up for a year is essential as a significant proportion of cases are initially negative and are only detected at a later stage. If the condition is diagnosed and treated early, the clinical response is excellent and the majority of cases are cured. PMID:24949443

  11. Chagas disease: changes in knowledge and management.

    PubMed

    Lescure, François-Xavier; Le Loup, Guillaume; Freilij, Hector; Develoux, Michel; Paris, Luc; Brutus, Laurent; Pialoux, Gilles

    2010-08-01

    More than 100 years after the discovery of human American trypanosomiasis by Carlos Chagas, our knowledge and management of the disease are profoundly changing. Substantial progress made by disease control programmes in most endemic areas contrasts with persisting difficulties in the Gran Chaco region in South America and the recent emergence of the disease in non-endemic areas because of population movements. In terms of pathogenesis, major discoveries have been made about the life cycle and genomics of Trypanosoma cruzi, and the role of the parasite itself in the chronic phase of the disease. From a clinical perspective, a growing number of arguments have challenged the notion of an indeterminate phase, and suggest new approaches to manage patients. New methods such as standardised PCR will be necessary to ensure follow-up of this chronic infection. Although drugs for treatment of Chagas disease are limited, poorly tolerated, and not very effective, treatment indications are expanding. The results of the Benznidazole Evaluation For Interrupting Trypanosomiasis (BENEFIT) trial in 2012 will also help to inform treatment. Mobilisation of financial resources to fund research on diagnosis and randomised controlled trials of treatment are international health priorities.

  12. Immunoregulatory networks in human Chagas disease

    PubMed Central

    Dutra, Walderez O.; Menezes, Cristiane A.S.; Magalhães, Luisa M. D.; Gollob, Kenneth J.

    2014-01-01

    Summary Chagas disease, caused by the infection with Trypanosoma cruzi, is endemic in all Latin America. Due to the increase in population migration, Chagas disease has spread worldwide and is now considered a health issue not only in endemic countries. While most chronically infected individuals remain asymptomatic, approximately 30% of the patients develop a potentially deadly cardiomyopathy. The exact mechanisms that underlie the establishment and maintenance of the cardiac pathology are not clear. However, there is consistent evidence that immunoregulatory cytokines are critical for orchestrating the immune response and, thus, influence disease development or control. While the asymptomatic (indeterminate) form represents a state of balance between the host and the parasite, the establishment of the cardiac form represents the loss of this balance. Analysis of data obtained from several studies have led to the hypothesis that the indeterminate form is associated with an anti-inflammatory cytokine profile, represented by high expression of IL-10, while cardiac form is associated with a high production of IFN-gamma and TNF-alpha in relation to IL-10, leading to an inflammatory profile. Here, we discuss the immunoregulatory events that might influence disease outcome, as well as the mechanisms that influence the establishment of these complex immunoregulatory networks. PMID:24611805

  13. [The third and new face of Chagas disease].

    PubMed

    Pays, J-F

    2016-08-01

    After the publication of the results of the BENEFIT study concluding that the benznidazole (5 mg/kg/d/60 d) is ineffective to stop the progression of the established Chagas' cardiomyopathy in adults, the author evokes the new experiences and the new challenges of 2016 regarding Chagas disease while speculating on its future and by calling back some elements little known of his history, in particular the fact that it is Chagas who invented about it to some extent the concept of "neglected disease".

  14. [The third and new face of Chagas disease].

    PubMed

    Pays, J-F

    2016-08-01

    After the publication of the results of the BENEFIT study concluding that the benznidazole (5 mg/kg/d/60 d) is ineffective to stop the progression of the established Chagas' cardiomyopathy in adults, the author evokes the new experiences and the new challenges of 2016 regarding Chagas disease while speculating on its future and by calling back some elements little known of his history, in particular the fact that it is Chagas who invented about it to some extent the concept of "neglected disease". PMID:27376642

  15. Prisms to Shift Pain Away: Pathophysiological and Therapeutic Exploration of CRPS with Prism Adaptation

    PubMed Central

    Volckmann, Pierre; Jacquin-Courtois, Sophie

    2016-01-01

    Complex Regional Pain Syndrome (CRPS) is an invalidating chronic condition subsequent to peripheral lesions. There is growing consensus for a central contribution to CRPS. However, the nature of this central body representation disorder is increasingly debated. Although it has been repeatedly argued that CRPS results in motor neglect of the affected side, visual egocentric reference frame was found to be deviated toward the pain, that is, neglect of the healthy side. Accordingly, prism adaptation has been successfully used to normalize this deviation. This study aimed at clarifying whether 7 CRPS patients exhibited neglect as well as exploring the pathophysiological mechanisms of this manifestation and of the therapeutic effects of prism adaptation. Pain and quality of life, egocentric reference frames (visual and proprioceptive straight-ahead), and neglect tests (line bisection, kinematic analyses of motor neglect and motor extinction) were repeatedly assessed prior to, during, and following a one-week intense prism adaptation intervention. First, our results provide no support for visual and motor neglect in CRPS. Second, reference frames for body representations were not systematically deviated. Third, intensive prism adaptation intervention durably ameliorated pain and quality of life. As for spatial neglect, understanding the therapeutic effects of prism adaptation deserves further investigations.

  16. Prisms to Shift Pain Away: Pathophysiological and Therapeutic Exploration of CRPS with Prism Adaptation

    PubMed Central

    Volckmann, Pierre; Jacquin-Courtois, Sophie

    2016-01-01

    Complex Regional Pain Syndrome (CRPS) is an invalidating chronic condition subsequent to peripheral lesions. There is growing consensus for a central contribution to CRPS. However, the nature of this central body representation disorder is increasingly debated. Although it has been repeatedly argued that CRPS results in motor neglect of the affected side, visual egocentric reference frame was found to be deviated toward the pain, that is, neglect of the healthy side. Accordingly, prism adaptation has been successfully used to normalize this deviation. This study aimed at clarifying whether 7 CRPS patients exhibited neglect as well as exploring the pathophysiological mechanisms of this manifestation and of the therapeutic effects of prism adaptation. Pain and quality of life, egocentric reference frames (visual and proprioceptive straight-ahead), and neglect tests (line bisection, kinematic analyses of motor neglect and motor extinction) were repeatedly assessed prior to, during, and following a one-week intense prism adaptation intervention. First, our results provide no support for visual and motor neglect in CRPS. Second, reference frames for body representations were not systematically deviated. Third, intensive prism adaptation intervention durably ameliorated pain and quality of life. As for spatial neglect, understanding the therapeutic effects of prism adaptation deserves further investigations. PMID:27668094

  17. Development of rotating prism mechanism and athermalized prism mounting for space

    NASA Astrophysics Data System (ADS)

    Beebe, Chip R.; Brooks, Mark J.; Davis, Michael W.; Klar, Robert A.; Roberts, John M.; Roming, Peter W. A.; Rose, Randall J.; Winters, Gregory S.

    2013-09-01

    Space and launch environments demand robust, low mass, and thermally insensitive mechanisms and optical mount designs. The rotating prism mechanism (RPM), a component of the stabilized dispersive focal plane system (SDFPS), is a spectral disperser mechanism that enables the SDFPS to deliver spectroscopic or direct imaging functionality using only a single optical path. The RPM is a redundant, vacuum-compatible, self-indexing, motorized mechanism that provides robust, athermalized prism mounting for two sets of matching prisms. Each set is composed of a BK7 and a CaF2 prism, both 70 mm in diameter. With the prism sets separated by 1 mm, the RPM rotates the two sets relative to one another over a 180° range, and maintains their alignment over a wide temperature range (190-308K). The RPM design incorporates self-indexing and backlash prevention features as well as redundant motors, bearings, and drive trains. The RPM was functionally tested in a thermal vacuum chamber at 210K and <1.0x10-6 mbar, and employed in the top-level SDFPS system testing. This paper presents the mechanical design, analysis, alignment measurements, and test results from the prototype RPM development effort.

  18. Evaluations of 1990 PRISM design revisions

    SciTech Connect

    Van Tuyle, G.J.; Slovik, G.C.; Chan, B.C.; Aronson, A.L.; Kennett, R.J.

    1992-03-01

    Analyses of the 1990 version of the PRISM Advanced Liquid Metal Reactor (ALMR) design are presented and discussed. Most of the calculations were performed using BNL computer codes, particularly SSC and MINET. In many cases, independent BNL calculations were compared against analyses presented by General Electric when they submitted the PRISM design revisions for evaluation by the Nuclear Regulatory Commission (NRC). The current PRISM design utilizes the metallic fuel developed by Argonne National Laboratory (ANL) which facilitates the passive/``inherent`` shutdown mechanism that acts to shut down reactor power production whenever the system overheats. There are a few vulnerabilities in the passive shutdown, with the most worrisome being the positive feedback from sodium density decreases or sodium voiding. Various postulated unscrammed events were examined by GE and/or BNL, and much of the analysis discussed in this report is focused on this category of events. For the most part, the BNL evaluations confirm the information submitted by General Electric. The principal areas of concern are related to the performance of the ternary metal fuel, and may be resolved as ANL continues with its fuel development and testing program.

  19. Compound prism design principles, III: linear-in-wavenumber and optical coherence tomography prisms.

    PubMed

    Hagen, Nathan; Tkaczyk, Tomasz S

    2011-09-01

    We extend the work of the first two papers in this series [Appl. Opt. 50, 4998-5011 (2011), Appl. Opt. 50, 5012-5022 (2011)] to design compound prisms for linear-in-wavenumber dispersion, especially for application in spectral domain optical coherence tomography (OCT). These dispersive prism designs are believed to be the first to meet the requirements of high resolution OCT systems in direct-view geometry, where they can be used to shrink system size, to improve light throughput, to reduce stray light, and to reduce errors resulting from interpolating between wavelength- and wavenumber-sampled domains. We show prism designs that can be used for thermal sources or for wideband superluminescent diodes centered around wavelengths 850, 900, 1300, and 1375 nm.

  20. American Trypanosomiasis (Also Known as Chagas Disease) Detailed FAQs

    MedlinePlus

    ... CDC Cancel Submit Search The CDC Parasites - American Trypanosomiasis (also known as Chagas Disease) Note: Javascript is ... cruzi infection) is also referred to as American trypanosomiasis. It is estimated that as many as 8 ...

  1. Tc-99m pyrophosphate myocardial scanning in Chagas' disease

    SciTech Connect

    da Rocha, A.F.; Meguerian, B.A.; Harbert, J.C.

    1981-04-01

    Chagas' disease is a serious protozoan infection affecting up to 20% of populations in some endemic areas. Myocarditis and cardiomyopathy occur in 50% of patients who go on to develop chronic Chagas' disease. We have studied a patient with no overt cardiac symptoms who revealed intense myocardial uptake of Tc-99m pyrophosphate. The significance of this finding in relation to early detection and progress of therapy is explored.

  2. Tc-99m pyrophosphate myocardial scanning in Chagas' disease

    SciTech Connect

    Goncalves da Rocha, A.F.; Meguerian, B.A.; Harbert, J.C.

    1981-04-01

    Chagas' disease is a serious protozoan infection affecting up to 20% of populations in some endemic areas. Myocarditis and cardiomyopathy occur in 50% of patients who go on to develop chronic Chagas's disease. We have studied a patient with no overt cardiac symptoms who revealed intense myocardial uptake of Tc-99m pyrophosphate. The significance of this finding in relation to early detection and progress of therapy is explored.

  3. Altered Cardiomyocyte Function and Trypanosoma cruzi Persistence in Chagas Disease.

    PubMed

    Cruz, Jader Santos; Santos-Miranda, Artur; Sales-Junior, Policarpo Ademar; Monti-Rocha, Renata; Campos, Paula Peixoto; Machado, Fabiana Simão; Roman-Campos, Danilo

    2016-05-01

    Chagas disease, caused by the triatominae Trypanosoma cruzi, is one of the leading causes of heart malfunctioning in Latin America. The cardiac phenotype is observed in 20-30% of infected people 10-40 years after their primary infection. The cardiac complications during Chagas disease range from cardiac arrhythmias to heart failure, with important involvement of the right ventricle. Interestingly, no studies have evaluated the electrical properties of right ventricle myocytes during Chagas disease and correlated them to parasite persistence. Taking advantage of a murine model of Chagas disease, we studied the histological and electrical properties of right ventricle in acute (30 days postinfection [dpi]) and chronic phases (90 dpi) of infected mice with the Colombian strain of T. cruzi and their correlation to parasite persistence. We observed an increase in collagen deposition and inflammatory infiltrate at both 30 and 90 dpi. Furthermore, using reverse transcriptase polymerase chain reaction, we detected parasites at 90 dpi in right and left ventricles. In addition, we observed action potential prolongation and reduced transient outward K(+) current and L-type Ca(2+) current at 30 and 90 dpi. Taking together, our results demonstrate that T. cruzi infection leads to important modifications in electrical properties associated with inflammatory infiltrate and parasite persistence in mice right ventricle, suggesting a causal role between inflammation, parasite persistence, and altered cardiomyocyte function in Chagas disease. Thus, arrhythmias observed in Chagas disease may be partially related to altered electrical function in right ventricle.

  4. Wollaston prism phase-stepping point diffraction interferometer and method

    DOEpatents

    Rushford, Michael C.

    2004-10-12

    A Wollaston prism phase-stepping point diffraction interferometer for testing a test optic. The Wollaston prism shears light into reference and signal beams, and provides phase stepping at increased accuracy by translating the Wollaston prism in a lateral direction with respect to the optical path. The reference beam produced by the Wollaston prism is directed through a pinhole of a diaphragm to produce a perfect spherical reference wave. The spherical reference wave is recombined with the signal beam to produce an interference fringe pattern of greater accuracy.

  5. Prism fingerprint sensor that uses a holographic optical element

    NASA Astrophysics Data System (ADS)

    Bahuguna, R. D.; Corboline, Tom

    1996-09-01

    A prism fingerprint sensor is described that uses a holographic grating glued to a right-angled prism. A light source normally illuminates the hypotenuse side of the prism with the finger pressed against the grating. The ridges and valleys of the finger are sensed on the basis of the principle of total internal reflection. The grating is used essentially to correct the distortion usually present with prism sensors. The quality of the fingerprint is very good: the pores on the ridges can be seen.

  6. Infrared hyperspectral imaging polarimeter using birefringent prisms.

    PubMed

    Craven-Jones, Julia; Kudenov, Michael W; Stapelbroek, Maryn G; Dereniak, Eustace L

    2011-03-10

    A compact short-wavelength and middle-wavelength infrared hyperspectral imaging polarimeter (IHIP) is introduced. The sensor includes a pair of sapphire Wollaston prisms and several high-order retarders to form an imaging Fourier transform spectropolarimeter. The Wollaston prisms serve as a birefringent interferometer with reduced sensitivity to vibration versus an unequal path interferometer, such as a Michelson. Polarimetric data are acquired through the use of channeled spectropolarimetry to modulate the spectrum with the Stokes parameter information. The collected interferogram is Fourier filtered and reconstructed to recover the spatially and spectrally varying Stokes vector data across the image. The IHIP operates over a ±5° field of view and implements a dual-scan false signature reduction technique to suppress polarimetric aliasing artifacts. In this paper, the optical layout and operation of the IHIP sensor are presented in addition to the radiometric, spectral, and polarimetric calibration techniques used with the system. Spectral and spectropolarimetric results from the laboratory and outdoor tests with the instrument are also presented. PMID:21394189

  7. Infrared hyperspectral imaging polarimeter using birefringent prisms.

    PubMed

    Craven-Jones, Julia; Kudenov, Michael W; Stapelbroek, Maryn G; Dereniak, Eustace L

    2011-03-10

    A compact short-wavelength and middle-wavelength infrared hyperspectral imaging polarimeter (IHIP) is introduced. The sensor includes a pair of sapphire Wollaston prisms and several high-order retarders to form an imaging Fourier transform spectropolarimeter. The Wollaston prisms serve as a birefringent interferometer with reduced sensitivity to vibration versus an unequal path interferometer, such as a Michelson. Polarimetric data are acquired through the use of channeled spectropolarimetry to modulate the spectrum with the Stokes parameter information. The collected interferogram is Fourier filtered and reconstructed to recover the spatially and spectrally varying Stokes vector data across the image. The IHIP operates over a ±5° field of view and implements a dual-scan false signature reduction technique to suppress polarimetric aliasing artifacts. In this paper, the optical layout and operation of the IHIP sensor are presented in addition to the radiometric, spectral, and polarimetric calibration techniques used with the system. Spectral and spectropolarimetric results from the laboratory and outdoor tests with the instrument are also presented.

  8. Chagas disease (American trypanosomiasis) in Mexico: an update.

    PubMed

    Carabarin-Lima, Alejandro; González-Vázquez, María Cristina; Rodríguez-Morales, Olivia; Baylón-Pacheco, Lidia; Rosales-Encina, José Luis; Reyes-López, Pedro Antonio; Arce-Fonseca, Minerva

    2013-08-01

    Chagas disease is a parasitic infection caused by the protozoan Trypanosoma cruzi, a flagellated organism that is transmitted mainly to humans through the infected feces of triatomine kissing bugs (vector transmission in endemic areas) or by transfusion of infected blood, donations of infected organ, or transmission from an infected mother to her child at birth. Chagas disease was first described in 1909 by the Brazilian physician Carlos Chagas, and due to the parasite's distribution throughout North, Central and South America, the disease is commonly known as American trypanosomiasis. However, this disease is now present in non-endemic countries such as Canada, the United States of America, and several countries in Europe (principally Spain). Moreover, Chagas disease was recently designated by the World Health Organization as one of the main neglected tropical diseases. The aim of this review is to summarize the research efforts recently described in studies conducted in Mexico on Chagas disease. In this country, there are no existing vector control programs. In addition, there is no consensus on the diagnostic methods for acute and chronic Chagas disease in maternity wards and blood banks, and trypanocidal therapy is not administered to chronic patients. The actual prevalence of the disease is unknown because no official reporting of cases is performed. Therefore, the number of people infected by different routes of transmission (vector, congenital, blood transfusion, organ transplantation, or oral) is unknown. We believe that by promoting education about Chagas disease in schools starting at the basic elementary level and including reinforcement at higher education levels will ensure that the Mexican population would be aware of this health problem and that the control measures adopted will have more acceptance and success. We hope that this review sensitizes the relevant authorities and that the appropriate measures to reduce the risk of infection by T. cruzi

  9. Priorities in School Mathematics: Executive Summary of the PRISM Project.

    ERIC Educational Resources Information Center

    National Council of Teachers of Mathematics, Inc., Reston, VA.

    The Priorities in School Mathematics Project (PRISM) was designed by the National Council of Teachers of Mathematics to collect information on current beliefs and reactions to possible mathematics curriculum changes during the 1980's. The first component of PRISM was a survey of preferences for alternative content topics, instructional goals,…

  10. New Light on a Prism: The Concert for All Reasons

    ERIC Educational Resources Information Center

    Linaberry, Robin

    2004-01-01

    The prism concert concept was introduced in this country at the Eastman School of Music in 1975. The development of Eastman's inaugural prism concert is commonly attributed to Donald Hunsberger and Gustav Meier, conductors of the wind ensemble and orchestra, respectively. The basic idea is that different styles of music performed by different…

  11. Prevention of congenital Chagas through treatment of girls and women of childbearing age

    PubMed Central

    Moscatelli, Guillermo; Moroni, Samanta; García-Bournissen, Facundo; Ballering, Griselda; Bisio, Margarita; Freilij, Héctor; Altcheh, Jaime

    2015-01-01

    It is currently unknown whether treatment of Chagas disease decreases the risk of congenital transmission from previously treated mothers to their infants. In a cohort of women with Chagas disease previously treated with benznidazole, no congenital transmission of the disease was observed in their newborns. This finding provides support for the treatment of Chagas disease as early as possible. PMID:25993401

  12. Acute Chagas disease in El Salvador 2000-2012 - Need for surveillance and control

    PubMed Central

    Sasagawa, Emi; de Aguilar, Ana Vilma Guevara; de Ramírez, Marta Alicia Hernández; Chévez, José Eduardo Romero; Nakagawa, Jun; Cedillos, Rafael Antonio; Kita, Kiyoshi

    2014-01-01

    Several parasitological studies carried out in El Salvador between 2000-2012 showed a higher frequency of acute cases of Chagas disease than that in other Central American countries. There is an urgent need for improved Chagas disease surveillance and vector control programs in the provinces where acute Chagas disease occurs and throughout El Salvador as a whole. PMID:24676660

  13. Neutral density filters with Risley prisms: analysis and design.

    PubMed

    Duma, Virgil-Florin; Nicolov, Mirela

    2009-05-10

    We achieve the analysis and design of optical attenuators with double-prism neutral density filters. A comparative study is performed on three possible device configurations; only two are presented in the literature but without their design calculus. The characteristic parameters of this optical attenuator with Risley translating prisms for each of the three setups are defined and their analytical expressions are derived: adjustment scale (attenuation range) and interval, minimum transmission coefficient and sensitivity. The setups are compared to select the optimal device, and, from this study, the best solution for double-prism neutral density filters, both from a mechanical and an optical point of view, is determined with two identical, symmetrically movable, no mechanical contact prisms. The design calculus of this optimal device is developed in essential steps. The parameters of the prisms, particularly their angles, are studied to improve the design, and we demonstrate the maximum attenuation range that this type of attenuator can provide.

  14. Rankine combined vortex interaction with a rectangular prism

    NASA Astrophysics Data System (ADS)

    Gorecki, Piotr; Panneer Selvam, Rathinam

    2015-01-01

    Large eddy simulation is utilised to study the three-dimensional interaction between a travelling Rankine combined vortex and a rectangular prism. The study examines the strength and the topology of a vortex during the interaction with a prism that is much wider than the vortex core diameter. The physics of the interaction is revealed for the straight (β = 0°) and the oblique (β = 45°) impacts. For both cases, the low-level portion of the vortex undergoes displacements in the streamwise and the lateral directions. Also the vortex shape and the core vorticity are substantially disrupted. Behind the prism the full vortex circulation is recovered after a considerable distance. This created a low-velocity region. The sheltering effect of the prism is noticed for both straight and oblique impacts. The flow velocities in the sheltering region, right behind the prism, are reduced by more than 42% compared to the maximum flow speeds before the interaction.

  15. Epidemiology of Chagas disease in Europe: many calculations, little knowledge.

    PubMed

    Strasen, Jörn; Williams, Tatjana; Ertl, Georg; Zoller, Thomas; Stich, August; Ritter, Oliver

    2014-01-01

    Chagas disease and its causative agent Trypanosoma cruzi are endemic in almost all countries in South and Middle America. Currently, there are more than 10 million affected people. It is the most common reason for heart failure and a frequent cause of intestinal problems in Latin America. The phenotype of the Chagas cardiomyopathy is varying. Dilative cardiomyopathy, often accompanied by an apical aneurysm is the most common finding in the end stage heart failure, but rhythm disorders like conduction blocks, ventricular or supraventricular forms of tachycardia or repolarization changes occur as well, mainly in the early stages. Migration of infected people leads to a distribution from the endemic countries to North America and Europe. Although more than 500,000 people of Latin American origin are currently living in Europe, Chagas disease is not considered as a public health problem, yet. Cases of transmission via blood donation, organ transplantation or from mother-to-child are reported for several European countries but there is no database for Germany. Current epidemiological data are mostly available from regional surveys from other countries or are extrapolated. Hence, there is a large variation in the estimated numbers on the incidence of Chagas. Robust and reliable data are lacking. This review gives an overview on the currently available data and calls for a German Chagas surveillance.

  16. Chronic Chagas disease: from basics to laboratory medicine.

    PubMed

    Haberland, Annekathrin; Saravia, Silvia Gilka Munoz; Wallukat, Gerd; Ziebig, Reinhard; Schimke, Ingolf

    2013-02-01

    Chagas disease, caused by Trypanosoma cruzi infection, is ranked as the most serious parasitic disease in Latin America and has huge potential to become a worldwide problem, due to increasing migration, and international tourism, as well as infectant transfer by blood contact and transfusion, intrauterine transfer, and organ transplantation. Nearly 30% of chronically-infected patients become symptomatic, often with a latency of 10-30 years, developing life-threatening complications. Of those, nearly 90% develop Chagas heart disease, while the others manifest gastrointestinal disease and neuronal disorders. Besides interrupting the infection cycle and chemo therapeutic infectant elimination, starting therapy early in symptomatic patients is important for counteracting the disease. This would be essentially supported by optimized patient management, involving risk assessment, early diagnosis and monitoring of the disease and its treatment. From economic and logistic viewpoints, the tools of laboratory medicine should be especially able to guarantee this. After summarizing the basics of chronic Chagas disease, such as the epidemiological data, the pathogenetic mechanisms thought to drive symptomatic Chagas disease and also treatment options, we present tools of laboratory medicine that address patient diagnosis, risk assessment for becoming symptomatic and guidance, focusing on autoantibody estimation for risk assessment and heart marker measurement for patient guidance. In addition, increases in levels of inflammation and oxidative stress markers in chronic Chagas disease are discussed.

  17. Motion control of the wedge prisms in Risley-prism-based beam steering system for precise target tracking.

    PubMed

    Zhou, Yuan; Lu, Yafei; Hei, Mo; Liu, Guangcan; Fan, Dapeng

    2013-04-20

    Two exact inverse solutions of Risley prisms have been given by previous authors, based on which we calculate the gradients of the scan field that open a way to investigate the nonlinear relationship between the slewing rate of the beam and the required angular velocities of the two wedge prisms in the Risley-prism-based beam steering system for target tracking. The limited regions and singularity point at the center and the edge of the field of regard are discussed. It is found that the maximum required rotational velocities of the two prisms for target tracking are nearly the same and are dependent on the altitude angle. The central limited region is almost independent of the prism parameters. The control singularity at the crossing center path can be avoided by switching the two solutions.

  18. Prisms and neglect: what have we learned?

    PubMed

    Newport, Roger; Schenk, Thomas

    2012-05-01

    Since Rossetti et al. (1998) reported that prism adaptation (PA) can lead to a substantial reduction of neglect symptoms PA has become a hot topic in neglect-research. More than 280 articles have been published in this area. Not all of those studies investigated the therapeutic potential of this technique, many studies examined the responsiveness to PA as a way to subdivide neglect into separate subsyndromes, other studies focussed on the process of PA itself in an effort to illuminate its underlying neurobiological mechanisms. In this article we will review research in all of these three areas to determine whether and to what extent research on PA in neglect patients has fulfilled its promise as a new way to improve the treatment of neglect, enhance our understanding of this complex syndrome and provide new insights into the neurobiology of sensorimotor learning.

  19. Active stereo vision routines using PRISM-3

    NASA Astrophysics Data System (ADS)

    Antonisse, Hendrick J.

    1992-11-01

    This paper describes work in progress on a set of visual routines and supporting capabilities implemented on the PRISM-3 real-time vision system. The routines are used in an outdoor robot retrieval task. The task requires the robot to locate a donor agent -- a Hero2000 -- which holds the object to be retrieved, to navigate to the donor, to accept the object from the donor, and return to its original location. The routines described here will form an integral part of the navigation and wide-area search tasks. Active perception is exploited to locate the donor using real-time stereo ranging directed by a pan/tilt/verge mechanism. A framework for orchestrating visual search has been implemented and is briefly described.

  20. Mechanisms underlying neglect recovery after prism adaptation.

    PubMed

    Serino, Andrea; Angeli, Valentina; Frassinetti, Francesca; Làdavas, Elisabetta

    2006-01-01

    Prism adaptation (PA) has been demonstrated to be effective in improving hemispatial neglect. However not all patients seem to benefit from this procedure. Thus, the objective of the present work is to provide behavioural and neuroanatomical predictors of recovery by exploring the reorganization of low-order visuo-motor behaviour and high-order visuo-spatial representation induced by PA. To this end, 16 neglect patients (experimental group) were submitted to a PA treatment for 10 daily sessions. Neglect and oculo-motor responses were assessed before the treatment, 1 week, 1 and 3 months after the treatment. Eight control patients, who received general cognitive stimulation, were submitted to the same tests at the same time interval. The results showed that experimental patients obtained, as a consequence of PA, a long lasting neglect recovery, a reorganization of low-order visuo-motor behaviour during and after prism exposure (error reduction and after-effect, respectively) and a leftward deviation of oculo-motor responses. Importantly, the level of error reduction obtained in the first week of treatment was predictive of neglect recovery and the amelioration of oculo-motor responses, and the degree of eye movement deviation was positively related to neglect amelioration. Finally, the study of patients' neuroanatomical data showed that severe occipital lesions were associated with a lack of error reduction, poor neglect recovery and reduced oculo-motor system amelioration. In conclusion, the present results suggest that low-order visuo-motor reorganization induced by PA promotes a resetting of the oculo-motor system leading to an improvement in high-order visuo-spatial representation able to ameliorate neglect. PMID:16330055

  1. Large beam deflection using cascaded prism array

    NASA Astrophysics Data System (ADS)

    Wang, Wei-Chih; Tsui, Chi-Leung

    2012-04-01

    Endoscopes have been utilize in the medical field to observe the internals of the human body to assist the diagnosis of diseases, such as breathing disorders, internal bleeding, stomach ulcers, and urinary tract infections. Endoscopy is also utilized in the procedure of biopsy for the diagnosis of cancer. Conventional endoscopes suffer from the compromise between overall size and image quality due to the required size of the sensor for acceptable image quality. To overcome the size constraint while maintaining the capture image quality, we propose an electro-optic beam steering device based on thermal-plastic polymer, which has a small foot-print (~5mmx5mm), and can be easily fabricated using conventional hot-embossing and micro-fabrication techniques. The proposed device can be implemented as an imaging device inside endoscopes to allow reduction in the overall system size. In our previous work, a single prism design has been used to amplify the deflection generated by the index change of the thermal-plastic polymer when a voltage is applied; it yields a result of 5.6° deflection. To further amplify the deflection, a new design utilizing a cascading three-prism array has been implemented and a deflection angle to 29.2° is observed. The new design amplifies the beam deflection, while keeping the advantage of simple fabrication made possible by thermal-plastic polymer. Also, a photo-resist based collimator lens array has been added to reduce and provide collimation of the beam for high quality imaging purposes. The collimator is able to collimate the exiting beam at 4 μm diameter for up to 25mm, which potentially allows high resolution image capturing.

  2. Behavioural biology of Chagas disease vectors

    PubMed Central

    Lazzari, Claudio Ricardo; Pereira, Marcos Horácio; Lorenzo, Marcelo Gustavo

    2013-01-01

    Many arthropod species have adopted vertebrate blood as their main food source. Blood is rich in nutrients and, except for the presence of parasites, sterile. However, this food source is not freely available, nor is obtaining it devoid of risk. It circulates inside vessels hidden underneath the skin of mobile hosts that are able to defend themselves and even predate the insects that try to feed on them. Thus, the haematophagous lifestyle is associated with major morphological, physiological and behavioural adaptations that have accumulated throughout the evolutionary history of the various lineages of blood-sucking arthropods. These adaptations have significant consequences for the evolution of parasites as well as for the epidemiology of vector-transmitted diseases. In this review article, we analyse various aspects of the behaviour of triatomine bugs to illustrate how each behavioural trait represents a particular adaptation to their close association with their hosts, which may easily turn into predators. Our aim is to offer to the reader an up-to-date integrative perspective on the behaviour of Chagas disease vectors and to propose new research avenues to encourage both young and experienced colleagues to explore this aspect of triatomine biology. PMID:24473801

  3. Novel cruzipain inhibitors for the chemotherapy of chronic Chagas disease.

    PubMed

    Sbaraglini, María L; Bellera, Carolina L; Fraccaroli, Laura; Larocca, Luciana; Carrillo, Carolina; Talevi, Alan; Alba Soto, Catalina D

    2016-07-01

    Despite current efforts worldwide to develop new medications against Chagas disease, only two drugs are available, nifurtimox and benznidazole. Both drugs require prolonged treatment and have multiple side effects and limited efficacy on adult patients chronically infected with Trypanosoma cruzi. Recently, computer-guided drug repositioning led to the discovery of the trypanocidal effects of clofazimine and benidipine. These compounds showed inhibitory effects on cruzipain, the major cysteine protease of T. cruzi, of different parasite stages and in a murine model of acute Chagas disease. The aim of this work was to determine the efficacy of these novel cruzipain inhibitors when administered in a murine model of chronic Chagas disease. Benidipine and clofazimine were able to reduce the parasite burden in cardiac and skeletal muscles of chronically infected mice compared with untreated mice as well as diminish the inflammatory process in these tissues. Further studies should be performed to study the synergism with benznidazole and nifurtimox in view of combined therapies.

  4. Goldmann Tonometer Prism with an Optimized Error Correcting Applanation Surface

    PubMed Central

    McCafferty, Sean; Lim, Garrett; Duncan, William; Enikov, Eniko; Schwiegerling, Jim

    2016-01-01

    Purpose We evaluate solutions for an applanating surface modification to the Goldmann tonometer prism, which substantially negates the errors due to patient variability in biomechanics. Methods A modified Goldmann or correcting applanation tonometry surface (CATS) prism is presented which was optimized to minimize the intraocular pressure (IOP) error due to corneal thickness, stiffness, curvature, and tear film. Mathematical modeling with finite element analysis (FEA) and manometric IOP referenced cadaver eyes were used to optimize and validate the design. Results Mathematical modeling of the optimized CATS prism indicates an approximate 50% reduction in each of the corneal biomechanical and tear film errors. Manometric IOP referenced pressure in cadaveric eyes demonstrates substantial equivalence to GAT in nominal eyes with the CATS prism as predicted by modeling theory. Conclusion A CATS modified Goldmann prism is theoretically able to significantly improve the accuracy of IOP measurement without changing Goldmann measurement technique or interpretation. Clinical validation is needed but the analysis indicates a reduction in CCT error alone to less than ±2 mm Hg using the CATS prism in 100% of a standard population compared to only 54% less than ±2 mm Hg error with the present Goldmann prism. Translational Relevance This article presents an easily adopted novel approach and critical design parameters to improve the accuracy of a Goldmann applanating tonometer.

  5. Pure rotation of a prism on a ramp

    PubMed Central

    Zhao, Zhen; Liu, Caishan; Ma, Daolin

    2014-01-01

    In this work, we study a prism with a cross section in polygon rolling on a ramp inclined at a small angle. The prism under gravity rolls purely around each individual edge, intermittently interrupted by a sequence of face collisions between the side face of the prism and the ramp. By limiting the prism in a planar motion, we propose a mathematical model to deal with the events of the impacts. With a pair of laser-Doppler vibrometers, experiments are also conducted to measure the motions of various prisms made of different materials and with different edge number. Not only are good agreements achieved between our numerical and experimental results, but also an intriguing physical phenomenon is discovered: the purely rolling motion is nearly independent of the prism's materials, yet it is closely related to the prism's geometry. Imagine that an ideal circular section can be approximately equivalent to a polygon with a large enough edge number N, the finding presented in this paper may help discover the physical mechanism of rolling friction. PMID:25197242

  6. Goldmann Tonometer Prism with an Optimized Error Correcting Applanation Surface

    PubMed Central

    McCafferty, Sean; Lim, Garrett; Duncan, William; Enikov, Eniko; Schwiegerling, Jim

    2016-01-01

    Purpose We evaluate solutions for an applanating surface modification to the Goldmann tonometer prism, which substantially negates the errors due to patient variability in biomechanics. Methods A modified Goldmann or correcting applanation tonometry surface (CATS) prism is presented which was optimized to minimize the intraocular pressure (IOP) error due to corneal thickness, stiffness, curvature, and tear film. Mathematical modeling with finite element analysis (FEA) and manometric IOP referenced cadaver eyes were used to optimize and validate the design. Results Mathematical modeling of the optimized CATS prism indicates an approximate 50% reduction in each of the corneal biomechanical and tear film errors. Manometric IOP referenced pressure in cadaveric eyes demonstrates substantial equivalence to GAT in nominal eyes with the CATS prism as predicted by modeling theory. Conclusion A CATS modified Goldmann prism is theoretically able to significantly improve the accuracy of IOP measurement without changing Goldmann measurement technique or interpretation. Clinical validation is needed but the analysis indicates a reduction in CCT error alone to less than ±2 mm Hg using the CATS prism in 100% of a standard population compared to only 54% less than ±2 mm Hg error with the present Goldmann prism. Translational Relevance This article presents an easily adopted novel approach and critical design parameters to improve the accuracy of a Goldmann applanating tonometer. PMID:27642540

  7. The Costs of Preventing and Treating Chagas Disease in Colombia

    PubMed Central

    Castillo-Riquelme, Marianela; Guhl, Felipe; Turriago, Brenda; Pinto, Nestor; Rosas, Fernando; Martínez, Mónica Flórez; Fox-Rushby, Julia; Davies, Clive; Campbell-Lendrum, Diarmid

    2008-01-01

    Background The objective of this study is to report the costs of Chagas disease in Colombia, in terms of vector disease control programmes and the costs of providing care to chronic Chagas disease patients with cardiomyopathy. Methods Data were collected from Colombia in 2004. A retrospective review of costs for vector control programmes carried out in rural areas included 3,084 houses surveyed for infestation with triatomine bugs and 3,305 houses sprayed with insecticide. A total of 63 patient records from 3 different hospitals were selected for a retrospective review of resource use. Consensus methodology with local experts was used to estimate care seeking behaviour and to complement observed data on utilisation. Findings The mean cost per house per entomological survey was $4.4 (in US$ of 2004), whereas the mean cost of spraying a house with insecticide was $27. The main cost driver of spraying was the price of the insecticide, which varied greatly. Treatment of a chronic Chagas disease patient costs between $46.4 and $7,981 per year in Colombia, depending on severity and the level of care used. Combining cost and utilisation estimates the expected cost of treatment per patient-year is $1,028, whereas lifetime costs averaged $11,619 per patient. Chronic Chagas disease patients have limited access to healthcare, with an estimated 22% of patients never seeking care. Conclusion Chagas disease is a preventable condition that affects mostly poor populations living in rural areas. The mean costs of surveying houses for infestation and spraying infested houses were low in comparison to other studies and in line with treatment costs. Care seeking behaviour and the type of insurance affiliation seem to play a role in the facilities and type of care that patients use, thus raising concerns about equitable access to care. Preventing Chagas disease in Colombia would be cost-effective and could contribute to prevent inequalities in health and healthcare. PMID:19015725

  8. Acquired Cell-Mediated Immunodepression in Acute Chagas' Disease

    PubMed Central

    Teixeira, Antonio R. L.; Teixeira, Glória; Macêdo, Vanize; Prata, Aluizio

    1978-01-01

    In this study two groups of patients with acute Chagas' disease were identified. Group one consisted of five patients with apparent acute Chagas' disease. These patients showed symptoms and signals of an acute illness, such as high fever and enlarged spleen. One of these patients developed severe myocarditis and heart failure. Group two consisted of seven patients with inapparent acute Chagas' disease. This was a nonclinical entity, not perceived by the patient who did not seek medical care. The diagnosis was made by the shift of a serologic test which indicates the presence of immunoglobulin M antibodies to Trypanosoma cruzi. The patients with apparent acute Chagas' disease showed positive delayed-type skin response to T. cruzi antigen. Also, their leukocytes showed significant inhibition of migration in the presence of this antigen. By contrast, the patients with the inapparent acute Chagas' disease did not show positive delayed-type skin response to T. cruzi antigen and no significant inhibition was observed when their cells migrated in the presence of this antigen. Of interest, none of these patients was capable of developing contact sensitivity to 2,4-dinitrochlorobenzene. However, three out of five patients with the apparent acute disease and all the normal control subjects showed positive contact reaction after sensitization to this drug. The results of these experiments would suggest that the thymus-derived (T)-lymphocyte function is depressed in patients with the clinically inapparent acute Chagas' disease. This immunodepression seems to be acquired in the course of the T. cruzi infection because all patients showed positive delayed-type skin response to at least one ubiquitous microbial extract, thus indicating previously normal T-cell function. We hypothesize that T. cruzi antigens may directly stimulate T cells with the concomitant release of factors that might become supressive for T-cell responses. Furthermore, the suppressive effect might interfere

  9. [Thermal spectral property of prism in hyper spectral imager].

    PubMed

    Liang, Jiu-Sheng; Wu, Qing-Wen; Li, Ze-Xue; Chen, Li-Heng; Guo, Liang

    2010-06-01

    Prism is one of the most key parts in the hyper spectral imager (HSI). Consequently, to set thermal control target and make thermal control design, the thermal spectral property of prism in the HSI was studied. The working principle of the HSI and the definition of its thermal spectral property were introduced. The working environment of prism and its thermal effect were analyzed; also the study contents and technical route of the prism's thermal spectral property were discussed. The effects of different uniform temperature field on deflexion angle and angular dispersion of the prism in the HSI were deduced, and the changes in displacement of the spectra and the spectral bandwidth under different uniform temperature were obtained. For one instance, the thermal spectral property of the K9 prism and the fused silica prism were compared based on FEM and combined experiments, furthermore, its thermal control target was ascertained and a thermal spectral property test was carried out to validate the rationality of the thermal spectral property analysis. The results of analysis indicated that the changes in spectral bandwidth and spectrum resolution brought by thermal distortions can be ignored according to current fixing mode, and the displacement of the spectra is mainly determined by thermal coefficient of material refractive index; because of it's the lower thermal coefficient of material refractive index, the displacement of the spectra of the K9 prism is smaller under the same temperature changes; the material deflexion changes (dn/dlambda) of prism are not sensitive to the temperature, so the changes in spectral bandwidth caused by them are not obvious. And the results of test proved that the studied method of thermal spectral property is reasonable and essential, and the results are authentic and credible. So it can provide some guidance for setting thermal control target and optimizing thermal control design. PMID:20707180

  10. Packing confined hard spheres denser with adaptive prism phases.

    PubMed

    Oğuz, Erdal C; Marechal, Matthieu; Ramiro-Manzano, Fernando; Rodriguez, Isabelle; Messina, René; Meseguer, Francisco J; Löwen, Hartmut

    2012-11-21

    We show that hard spheres confined between two parallel hard plates pack denser with periodic adaptive prismatic structures which are composed of alternating prisms of spheres. The internal structure of the prisms adapts to the slit height which results in close packings for a range of plate separations, just above the distance where three intersecting square layers fit exactly between the plates. The adaptive prism phases are also observed in real-space experiments on confined sterically stabilized colloids and in Monte Carlo simulations at finite pressure.

  11. Diffraction intensity analysis of a transmission prism grating

    NASA Astrophysics Data System (ADS)

    Liu, Xiaoyu; Zhang, Guosheng

    2010-11-01

    Because of the inherent structures, most common gratings always produce an unexpected loss of the input signal, which limits the use of gratings in many fields to some extent. Considering that, a design of grating with many periodical micro isosceles prisms is proposed. Based on the scalar diffraction theory, the transmittance is derived from the definition of an optical path when a parallel light passes through a singular prism element. And according to the multi-slit Fraunhofer diffraction, the expression of light intensity distribution for the prism grating on the frequency plane is deduced and analyzed by means of Fourier transform.

  12. Interrupting Chagas disease transmission in Venezuela.

    PubMed

    Aché, A; Matos, A J

    2001-01-01

    The interruption of vectorial transmission of Chagas disease in Venezuela is attributed to the combined effects of ongoing entomoepidemiological surveillance, ongoing house spraying with residual insecticides and the concurrent building and modification of rural houses in endemic areas during almost five decades. The original endemic areas which totaled 750,000 km(2), have been reduced to 365,000 km(2). During 1958-1968, initial entomological evaluations carried out showed that the house infestation index ranged between 60-80%, the house infection index at 8-11% and a house density index of 30-50 triatomine bugs per house. By 1990-98, these indexes were further reduced to 1.6-4.0%, 0.01-0.6% and 3-4 bugs per house respectively. The overall rural population seroprevalence has declined from 44.5% (95% C.I.: 43.4-45.3%) to 9.2% (95% C.I.: 9.0-9.4%) for successive grouped periods from 1958 to 1998. The annual blood donor prevalence is firmly established below 1%. The population at risk of infection has been estimated to be less than four million. Given that prevalence rates are stable and appropriate for public health programmes, consideration has been given to potential biases that may distort results such as: a) geographical differences in illness or longevity of patients; b) variations in levels of ascertainment; c) variations in diagnostic criteria; and d) variations in population structure, mainly due to appreciable population migration. The endemic areas with continuous transmission are now mainly confined to piedmonts, as well as patchy foci in higher mountainous ranges, where the exclusive vector is Rhodnius prolixus. There is also an unstable area, of which landscapes are made up of grasslands with scattered broad-leaved evergreen trees and costal plains, where transmission is very low and occasional outbreaks are reported.

  13. Strongly-Refractive One-Dimensional Photonic Crystal Prisms

    NASA Technical Reports Server (NTRS)

    Ting, David Z. (Inventor)

    2004-01-01

    One-dimensional (1D) photonic crystal prisms can separate a beam of polychromatic electromagnetic waves into constituent wavelength components and can utilize unconventional refraction properties for wavelength dispersion over significant portions of an entire photonic band rather than just near the band edges outside the photonic band gaps. Using a ID photonic crystal simplifies the design and fabrication process and allows the use of larger feature sizes. The prism geometry broadens the useful wavelength range, enables better optical transmission, and exhibits angular dependence on wavelength with reduced non-linearity. The properties of the 1 D photonic crystal prism can be tuned by varying design parameters such as incidence angle, exit surface angle, and layer widths. The ID photonic crystal prism can be fabricated in a planar process, and can be used as optical integrated circuit elements.

  14. Prism design based on changes in image orientation.

    PubMed

    Tsai, Chuang-Yu; Lin, Psang Dain

    2006-06-10

    We present a method of designing a prism to produce an image with a specific orientation. Traditional prism design of this kind is done by trial and error with the aid of geometrical drawing and cannot provide analytical results. Using skew ray tracing sensitivity analysis, we present a merit function that can specify changes in image orientation after the image is reflected by an arbitrary number of flat boundary surfaces. Two design approaches are proposed. One can produce a prism with a minimum number of flat boundary surfaces with the aid of an auxiliary unit vector. The other can produce many configurations of prisms but without the above feature. An illustrative example is used to demonstrate the validity of the proposed approaches. Eight new configurations, which can produce the same change in image orientation, are obtained from the proposed design approaches.

  15. 3. ELEVATION. FROM SOUTH WITH CANAL PRISM. Canal Road ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    3. ELEVATION. FROM SOUTH WITH CANAL PRISM. - Canal Road Bridge, Canal Road spanning Delaware Canal Diversion, Locks 22 & 23 in Delaware Canal State Park in Williams Township, Raubsville, Northampton County, PA

  16. Prisms with total internal reflection as solar reflectors

    DOEpatents

    Rabl, Arnulf; Rabl, Veronika

    1978-01-01

    An improved reflective wall for radiant energy collection and concentration devices is provided. The wall is comprised of a plurality of prisms whose frontal faces are adjacent and which reflect the desired radiation by total internal reflection.

  17. NORTHERLY STRETCH OF MILLBURY PORTION; GENERAL VIEW ACROSS CANAL PRISM ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    NORTHERLY STRETCH OF MILLBURY PORTION; GENERAL VIEW ACROSS CANAL PRISM TO TOWPATH BERM (LATER FILL ENCROACHING LEFT) NEAR CENTER OF THIS STRETCH; VIEW TO SOUTHWEST - Blackstone Canal Worcester-Millbury Segment, Eastern bank of Blackstone River, Millbury, Worcester County, MA

  18. Development of an unbonded capping system for clay masonry prisms

    SciTech Connect

    Crouch, L.K.; Henderson, R.C.; Sneed, W.A. Jr.

    1999-07-01

    To ascertain if an unbonded capping system was feasible for clay masonry prisms, the compressive strengths of thirty clay masonry prisms capped with an unbonded capping system modeled after ASTM C 1231 were compared with those of thirty masonry prisms capped with ASTM C 67 approved high-strength gypsum cement at the ages of 7 and 28 days. All prisms were constructed by a professional mason using Grade SW, Type FBS cored face brick from the same lot and ASTM C 270 Type S PC-lime mortar. There was no significant difference in mean compressive strength for the two capping methods at either age. In addition, capping with the unbonded capping system was faster and easier. Further, 28-day results obtained using the unbonded capping system had a lower coefficient of variation and higher mean compressive strength than those obtained with high-strength gypsum.

  19. 5. VIEW NORTHWEST SHOWING AQUEDUCT PRISM. NOTE INTERIOR STONE WORK ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    5. VIEW NORTHWEST SHOWING AQUEDUCT PRISM. NOTE INTERIOR STONE WORK OF THE PARAPET WALL AND REMAINS OF 1920 TIMBER AND CONCRETE FLOORING SYSTEM. - Chesapeake & Ohio Canal, Conococheague Creek Aqueduct, Milepost 99.80, Williamsport, Washington County, MD

  20. Ipsidirectional impairment of prism adaptation after unilateral lesion of anterior cerebellum.

    PubMed

    Pisella, L; Rossetti, Y; Michel, C; Rode, G; Boisson, D; Pélisson, D; Tilikete, C

    2005-07-12

    In a patient with damage of the left cerebellar cortex (SCA territory), the authors tested four combinations of exposure to optical shift (leftward prisms, right hand; rightward prisms, right hand; leftward prisms, left (ataxic) hand; rightward prisms, left (ataxic) hand). He adapted to rightward but not leftward prisms, independent of which hand was used during exposure. This suggests a role of anterior cerebellar cortex in the computation or compensation of ipsidirectional visual error.

  1. Vector Blood Meals and Chagas Disease Transmission Potential, United States

    PubMed Central

    Dorn, Patricia L.; Hobson, Julia; de la Rua, Nicholas M.; Lucero, David E.; Klotz, John H.; Schmidt, Justin O.; Klotz, Stephen A.

    2012-01-01

    A high proportion of triatomine insects, vectors for Trypanosoma cruzi trypanosomes, collected in Arizona and California and examined using a novel assay had fed on humans. Other triatomine insects were positive for T. cruzi parasite infection, which indicates that the potential exists for vector transmission of Chagas disease in the United States. PMID:22469536

  2. Proteomic profile of circulating immune complexes in chronic Chagas disease.

    PubMed

    Ohyama, K; Huy, N T; Yoshimi, H; Kishikawa, N; Nishizawa, J E; Roca, Y; Revollo Guzmán, R J; Velarde, F U G; Kuroda, N; Hirayama, K

    2016-10-01

    Immune complexes (ICs) are the direct and real-time products of humoral immune responses. The identification of constituent foreign or autoantigens within ICs might bring new insights into the pathology of infectious diseases. We applied immune complexome analysis of plasma to the study of Chagas disease caused by Trypanosoma cruzi. Twenty seropositive plasma samples including cardiac and/or megacolon determinate patients (n = 11) and indeterminate (n = 9) were analysed along with 10 seronegative individuals to characterize the antigens bound to circulating ICs. We identified 39 T. cruzi antigens and 114 human autoantigens specific to patients with Chagas. Among those antigens, two T. cruzi antigens (surface protease GP63, glucose-6-isomerase) and six human autoantigens (CD180 antigen, ceruloplasmin, fibrinogen beta chain, fibrinogen beta chain isoform 2 preprotein, isoform gamma-A of fibrinogen γ-chain, serum paraoxonase) were detected in more than 50% of the patients tested. Human isoform short of complement factor H-related protein 2 and trans-sialidase of T. cruzi were more frequently found in the indeterminate (5/9 for both) compared with in the determinate Chagas (0/11, P = 0·046 for human, 1/11, P = 0·0498 for T. cruzi). The immune complexome could illustrate the difference of immune status between clinical forms of chronic Chagas disease.

  3. Experimental Vaccines against Chagas Disease: A Journey through History.

    PubMed

    Rodríguez-Morales, Olivia; Monteón-Padilla, Víctor; Carrillo-Sánchez, Silvia C; Rios-Castro, Martha; Martínez-Cruz, Mariana; Carabarin-Lima, Alejandro; Arce-Fonseca, Minerva

    2015-01-01

    Chagas disease, or American trypanosomiasis, which is caused by the protozoan parasite Trypanosoma cruzi, is primarily a vector disease endemic in 21 Latin American countries, including Mexico. Although many vector control programs have been implemented, T. cruzi has not been eradicated. The development of an anti-T. cruzi vaccine for prophylactic and therapeutic purposes may significantly contribute to the transmission control of Chagas disease. Immune protection against experimental infection with T. cruzi has been studied since the second decade of the last century, and many types of immunogens have been used subsequently, such as killed or attenuated parasites and new DNA vaccines. This primary prevention strategy appears feasible, effective, safe, and inexpensive, although problems remain. The objective of this review is to summarize the research efforts about the development of vaccines against Chagas disease worldwide. A thorough literature review was conducted by searching PubMed with the terms "Chagas disease" and "American trypanosomiasis" together with "vaccines" or "immunization". In addition, reports and journals not cited in PubMed were identified. Publications in English, Spanish, and Portuguese were reviewed.

  4. Pathogenesis of Chagas' Disease: Parasite Persistence and Autoimmunity

    PubMed Central

    Teixeira, Antonio R. L.; Hecht, Mariana M.; Guimaro, Maria C.; Sousa, Alessandro O.; Nitz, Nadjar

    2011-01-01

    Summary: Acute Trypanosoma cruzi infections can be asymptomatic, but chronically infected individuals can die of Chagas' disease. The transfer of the parasite mitochondrial kinetoplast DNA (kDNA) minicircle to the genome of chagasic patients can explain the pathogenesis of the disease; in cases of Chagas' disease with evident cardiomyopathy, the kDNA minicircles integrate mainly into retrotransposons at several chromosomes, but the minicircles are also detected in coding regions of genes that regulate cell growth, differentiation, and immune responses. An accurate evaluation of the role played by the genotype alterations in the autoimmune rejection of self-tissues in Chagas' disease is achieved with the cross-kingdom chicken model system, which is refractory to T. cruzi infections. The inoculation of T. cruzi into embryonated eggs prior to incubation generates parasite-free chicks, which retain the kDNA minicircle sequence mainly in the macrochromosome coding genes. Crossbreeding transfers the kDNA mutations to the chicken progeny. The kDNA-mutated chickens develop severe cardiomyopathy in adult life and die of heart failure. The phenotyping of the lesions revealed that cytotoxic CD45, CD8+ γδ, and CD8α+ T lymphocytes carry out the rejection of the chicken heart. These results suggest that the inflammatory cardiomyopathy of Chagas' disease is a genetically driven autoimmune disease. PMID:21734249

  5. Chagas disease: Present status of pathogenic mechanisms and chemotherapy.

    PubMed

    Maya, Juan Diego; Orellana, Myriam; Ferreira, Jorge; Kemmerling, Ulrike; López-Muñoz, Rodrigo; Morello, Antonio

    2010-01-01

    There are approximately 7.8 million people in Latin America, including Chile, who suffer from Chagas disease and another 28 million who are at risk of contracting it. Chagas is caused by the flagellate protozoan Trypanosoma cruzi. It is a chronic disease, where 20%-30% of infected individuals develop severe cardiopathy, with heart failure and potentially fatal arrhythmias. Currently, Chagas disease treatment is more effective in the acute phase, but does not always produce complete parasite eradication during indeterminate and chronic phases. At present, only nifurtimox or benznidazole have been proven to be superior to new drugs being tested. Therefore, it is necessary to find alternative approaches to treatment of chronic Chagas. The current treatment may be rendered more effective by increasing the activity of anti-Chagasic drugs or by modifying the host's immune response. We have previously shown that glutathione synthesis inhibition increases nifurtimox and benznidazole activity. In addition, there is increasing evidence that cyclooxygenase inhibitors present an important effect on T. cruzi infection. Therefore, we found that aspirin reduced the intracellular infection in RAW 264.7 cells and, decreased myocarditis extension and mortality rates in mice. However, the long-term benefit of prostaglandin inhibition for Chagasic patients is still unknown.

  6. Experimental Vaccines against Chagas Disease: A Journey through History

    PubMed Central

    Rodríguez-Morales, Olivia; Monteón-Padilla, Víctor; Carrillo-Sánchez, Silvia C.; Rios-Castro, Martha; Martínez-Cruz, Mariana; Carabarin-Lima, Alejandro; Arce-Fonseca, Minerva

    2015-01-01

    Chagas disease, or American trypanosomiasis, which is caused by the protozoan parasite Trypanosoma cruzi, is primarily a vector disease endemic in 21 Latin American countries, including Mexico. Although many vector control programs have been implemented, T. cruzi has not been eradicated. The development of an anti-T. cruzi vaccine for prophylactic and therapeutic purposes may significantly contribute to the transmission control of Chagas disease. Immune protection against experimental infection with T. cruzi has been studied since the second decade of the last century, and many types of immunogens have been used subsequently, such as killed or attenuated parasites and new DNA vaccines. This primary prevention strategy appears feasible, effective, safe, and inexpensive, although problems remain. The objective of this review is to summarize the research efforts about the development of vaccines against Chagas disease worldwide. A thorough literature review was conducted by searching PubMed with the terms “Chagas disease” and “American trypanosomiasis” together with “vaccines” or “immunization”. In addition, reports and journals not cited in PubMed were identified. Publications in English, Spanish, and Portuguese were reviewed. PMID:26090490

  7. American trypanosomiasis (Chagas' disease) in a Canadian immigrant infant.

    PubMed

    Montalvo-Hicks, L D; Trevenen, C L; Briggs, J N

    1980-08-01

    A case of American trypanosomiasis (Chagas' disease) is reported. A 13-month-old Mennonite girl who immigrated to Canada from Paraguay, died at the Children's Centre in Winnipeg from an acute myocarditis due to infection with Trypanosoma cruzi. This diagnosis should be considered when a patient from an endemic area presents with a clinical picture of myocarditis.

  8. Negative Refraction experiments in Photonic Crystal prisms

    NASA Astrophysics Data System (ADS)

    Vodo, Plarenta; Parimi, Patanjali. V.; Lu, Wentao. T.; di Gennaro, Emiliano; Sridhar, Srinivas

    2004-03-01

    We have experimentally demonstrated negative refraction in metallic photonic crystal (PC) prisms [1]. The refracted fields in the parallel plate waveguide (PPW) are measured by an automated dipole antenna, which scans the desired area, while the free space (FS) measurements, performed in a anechoic chamber, are measured by a rectangular X-band horn that swings in an arc in far field area. Both TE and TM excitation modes are used in FS experiments. Numerical calculations of the band structure and equi-frequency surface simulations are used to determine frequency regions of negative refraction of the triangular lattice PC. Angle of refraction determined by theoretical simulations and experimental results, are in exceptional good agreement, yielding the negative refraction index. FS and PPW refraction experimental results agree remarkably with simulations. 1. "Negative Refraction and Left-handed electromagnetism in Microwave Photonic Crystals", P.V Parimi, W.T Lu, P.Vodo J. Sokoloff and S.Sridhar, cond-mat/0306109 (2003)

  9. APEX - the Hyperspectral ESA Airborne Prism Experiment

    PubMed Central

    Itten, Klaus I.; Dell'Endice, Francesco; Hueni, Andreas; Kneubühler, Mathias; Schläpfer, Daniel; Odermatt, Daniel; Seidel, Felix; Huber, Silvia; Schopfer, Jürg; Kellenberger, Tobias; Bühler, Yves; D'Odorico, Petra; Nieke, Jens; Alberti, Edoardo; Meuleman, Koen

    2008-01-01

    The airborne ESA-APEX (Airborne Prism Experiment) hyperspectral mission simulator is described with its distinct specifications to provide high quality remote sensing data. The concept of an automatic calibration, performed in the Calibration Home Base (CHB) by using the Control Test Master (CTM), the In-Flight Calibration facility (IFC), quality flagging (QF) and specific processing in a dedicated Processing and Archiving Facility (PAF), and vicarious calibration experiments are presented. A preview on major applications and the corresponding development efforts to provide scientific data products up to level 2/3 to the user is presented for limnology, vegetation, aerosols, general classification routines and rapid mapping tasks. BRDF (Bidirectional Reflectance Distribution Function) issues are discussed and the spectral database SPECCHIO (Spectral Input/Output) introduced. The optical performance as well as the dedicated software utilities make APEX a state-of-the-art hyperspectral sensor, capable of (a) satisfying the needs of several research communities and (b) helping the understanding of the Earth's complex mechanisms.

  10. PRISM: a planned risk information seeking model.

    PubMed

    Kahlor, LeeAnn

    2010-06-01

    Recent attention on health-related information seeking has focused primarily on information seeking within specific health and health risk contexts. This study attempts to shift some of that focus to individual-level variables that may impact health risk information seeking across contexts. To locate these variables, the researcher posits an integrated model, the Planned Risk Information Seeking Model (PRISM). The model, which treats risk information seeking as a deliberate (planned) behavior, maps variables found in the Theory of Planned Behavior (TPB; Ajzen, 1991) and the Risk Information Seeking and Processing Model (RISP; Griffin, Dunwoody, & Neuwirth, 1999), and posits linkages among those variables. This effort is further informed by Kahlor's (2007) Augmented RISP, the Theory of Motivated Information Management (Afifi & Weiner, 2004), the Comprehensive Model of Information Seeking (Johnson & Meischke, 1993), the Health Information Acquisition Model (Freimuth, Stein, & Kean, 1989), and the Extended Parallel Processing Model (Witte, 1998). The resulting integrated model accounted for 59% of the variance in health risk information-seeking intent and performed better than the TPB or the RISP alone. PMID:20512716

  11. Chagas disease: control, elimination and eradication. Is it possible?

    PubMed

    Coura, José Rodrigues

    2013-12-01

    From an epidemiological point of view, Chagas disease and its reservoirs and vectors can present the following characteristics: (i) enzooty, maintained by wild animals and vectors, with broad occurrence from southern United States of America (USA) to southern Argentina and Chile (42ºN 49ºS), (ii) anthropozoonosis, when man invades the wild ecotope and becomes infected with Trypanosoma cruzi from wild animals or vectors or when the vectors and wild animals, especially marsupials, invade the human domicile and infect man, (iii) zoonosis-amphixenosis and exchanged infection between animals and humans by domestic vectors in endemic areas and (iv) zooanthroponosis, infection that is transmitted from man to animals, by means of domestic vectors, which is the rarest situation in areas endemic for Chagas disease. The characteristics of Chagas disease as an enzooty of wild animals and as an anthropozoonosis are seen most frequently in the Brazilian Amazon and in the Pan-Amazon region as a whole, where there are 33 species of six genera of wild animals: Marsupialia, Chiroptera, Rodentia, Edentata (Xenarthra), Carnivora and Primata and 27 species of triatomines, most of which infected with T. cruzi . These conditions place the resident populations of this area or its visitors - tourists, hunters, fishermen and especially the people whose livelihood involves plant extraction - at risk of being affected by Chagas disease. On the other hand, there has been an exponential increase in the acute cases of Chagas disease in that region through oral transmission of T. cruzi , causing outbreaks of the disease. In four seroepidemiological surveys that were carried out in areas of the microregion of the Negro River, state of Amazonas, in 1991, 1993, 1997 and 2010, we found large numbers of people who were serologically positive for T. cruzi infection. The majority of them and/or their relatives worked in piassava extraction and had come into contact with and were stung by wild

  12. Chagas disease: control, elimination and eradication. Is it possible?

    PubMed Central

    Coura, José Rodrigues

    2013-01-01

    From an epidemiological point of view, Chagas disease and its reservoirs and vectors can present the following characteristics: (i) enzooty, maintained by wild animals and vectors, with broad occurrence from southern United States of America (USA) to southern Argentina and Chile (42ºN 49ºS), (ii) anthropozoonosis, when man invades the wild ecotope and becomes infected with Trypanosoma cruzi from wild animals or vectors or when the vectors and wild animals, especially marsupials, invade the human domicile and infect man, (iii) zoonosis-amphixenosis and exchanged infection between animals and humans by domestic vectors in endemic areas and (iv) zooanthroponosis, infection that is transmitted from man to animals, by means of domestic vectors, which is the rarest situation in areas endemic for Chagas disease. The characteristics of Chagas disease as an enzooty of wild animals and as an anthropozoonosis are seen most frequently in the Brazilian Amazon and in the Pan-Amazon region as a whole, where there are 33 species of six genera of wild animals: Marsupialia, Chiroptera, Rodentia, Edentata (Xenarthra), Carnivora and Primata and 27 species of triatomines, most of which infected with T. cruzi . These conditions place the resident populations of this area or its visitors - tourists, hunters, fishermen and especially the people whose livelihood involves plant extraction - at risk of being affected by Chagas disease. On the other hand, there has been an exponential increase in the acute cases of Chagas disease in that region through oral transmission of T. cruzi , causing outbreaks of the disease. In four seroepidemiological surveys that were carried out in areas of the microregion of the Negro River, state of Amazonas, in 1991, 1993, 1997 and 2010, we found large numbers of people who were serologically positive for T. cruzi infection. The majority of them and/or their relatives worked in piassava extraction and had come into contact with and were stung by wild

  13. Current drug therapy and pharmaceutical challenges for Chagas disease.

    PubMed

    Bermudez, José; Davies, Carolina; Simonazzi, Analía; Real, Juan Pablo; Palma, Santiago

    2016-04-01

    One of the most significant health problems in the American continent in terms of human health, and socioeconomic impact is Chagas disease, caused by the protozoan parasite Trypanosoma cruzi. Infection was originally transmitted by reduviid insects, congenitally from mother to fetus, and by oral ingestion in sylvatic/rural environments, but blood transfusions, organ transplants, laboratory accidents, and sharing of contaminated syringes also contribute to modern day transmission. Likewise, Chagas disease used to be endemic from Northern Mexico to Argentina, but migrations have earned it global. The parasite has a complex life cycle, infecting different species, and invading a variety of cells - including muscle and nerve cells of the heart and gastrointestinal tract - in the mammalian host. Human infection outcome is a potentially fatal cardiomyopathy, and gastrointestinal tract lesions. In absence of a vaccine, vector control and treatment of patients are the only tools to control the disease. Unfortunately, the only drugs now available for Chagas' disease, Nifurtimox and Benznidazole, are relatively toxic for adult patients, and require prolonged administration. Benznidazole is the first choice for Chagas disease treatment due to its lower side effects than Nifurtimox. However, different strategies are being sought to overcome Benznidazole's toxicity including shorter or intermittent administration schedules-either alone or in combination with other drugs. In addition, a long list of compounds has shown trypanocidal activity, ranging from natural products to specially designed molecules, re-purposing drugs commercialized to treat other maladies, and homeopathy. In the present review, we will briefly summarize the upturns of current treatment of Chagas disease, discuss the increment on research and scientific publications about this topic, and give an overview of the state-of-the-art research aiming to produce an alternative medication to treat T. cruzi infection.

  14. Chagas disease in a Texan horse with neurologic deficits.

    PubMed

    Bryan, Laura K; Hamer, Sarah A; Shaw, Sarah; Curtis-Robles, Rachel; Auckland, Lisa D; Hodo, Carolyn L; Chaffin, Keith; Rech, Raquel R

    2016-01-30

    A 10-year-old Quarter Horse gelding presented to the Texas A&M University Veterinary Teaching Hospital with a six month-history of ataxia and lameness in the hind limbs. The horse was treated presumptively for equine protozoal myeloencephalitis (EPM) based on clinical signs but was ultimately euthanized after its condition worsened. Gross lesions were limited to a small area of reddening in the gray matter of the thoracic spinal cord. Histologically, trypanosome amastigotes morphologically similar to Trypanosoma cruzi, the agent of Chagas disease in humans and dogs, were sporadically detected within segments of the thoracic spinal cord surrounded by mild lymphoplasmacytic inflammation. Ancillary testing for Sarcocystis neurona, Neospora spp., Toxoplasma gondii and Leishmania spp. was negative. Conventional and real time polymerase chain reaction (PCR) of affected paraffin embedded spinal cord were positive for T. cruzi, and sequencing of the amplified T. cruzi satellite DNA PCR fragment from the horse was homologous with various clones of T. cruzi in GenBank. While canine Chagas disease cases have been widely reported in southern Texas, this is the first report of clinical T. cruzi infection in an equid with demonstrable amastigotes in the spinal cord. In contrast to previous instances of Chagas disease in the central nervous system (CNS) of dogs and humans, no inflammation or T. cruzi amastigotes were detected in the heart of the horse. Based on clinical signs, there is a potential for misdiagnosis of Chagas disease with other infectious diseases that affect the equine CNS. T. cruzi should be considered as a differential diagnosis in horses with neurologic clinical signs and histologic evidence of meningomyelitis that originate in areas where Chagas disease is present. The prevalence of T. cruzi in horses and the role of equids in the parasite life cycle require further study.

  15. The burden of Chagas disease: estimates and challenges.

    PubMed

    Stanaway, Jeffrey D; Roth, Gregory

    2015-09-01

    Chagas disease, caused by infection with the protozoa Trypanosoma cruzi is transmitted most often by Triatominae insect vectors, but also through blood transfusion, organ transplant, and congenital transmission. Between 5 and 18 million people are currently infected and the infection is estimated to cause more than 10,000 deaths annually. The disease has 3 phases: acute, indeterminate, and chronic. The acute phase immediately follows infection. It is typically asymptomatic but produces fever and malaise in up to 5% of people. The indeterminate phase is asymptomatic. More than one-half of those infected will remain in this phase for life and never experience long-term sequelae. After a decade or more, 20% to 30% of people will experience chronic cardiovascular Chagas disease with sequelae including heart failure, arrhythmias, and thromboembolism. Another 15% to 20% will experience chronic digestive sequela including megaesophagus and megacolon. A complete accounting of the burden of Chagas disease requires estimating the prevalence of the infection, the prevalence of each of its sequelae among those with the infection, and the number of deaths attributable to the infection. Attempts to estimate Chagas disease prevalence are complicated by several challenges imposed by the disease's extreme spatial heterogeneity, quickly evolving temporal trends, the decades-long lag between infection and symptomatic disease, biased prevalence data, incomplete recognition of Chagas-attributable deaths, limited data on sequela, and a near total absence of data outside of endemic countries. Even though researchers have found methodological approaches to dealing with these challenges, there is a need for better data.

  16. Current drug therapy and pharmaceutical challenges for Chagas disease.

    PubMed

    Bermudez, José; Davies, Carolina; Simonazzi, Analía; Real, Juan Pablo; Palma, Santiago

    2016-04-01

    One of the most significant health problems in the American continent in terms of human health, and socioeconomic impact is Chagas disease, caused by the protozoan parasite Trypanosoma cruzi. Infection was originally transmitted by reduviid insects, congenitally from mother to fetus, and by oral ingestion in sylvatic/rural environments, but blood transfusions, organ transplants, laboratory accidents, and sharing of contaminated syringes also contribute to modern day transmission. Likewise, Chagas disease used to be endemic from Northern Mexico to Argentina, but migrations have earned it global. The parasite has a complex life cycle, infecting different species, and invading a variety of cells - including muscle and nerve cells of the heart and gastrointestinal tract - in the mammalian host. Human infection outcome is a potentially fatal cardiomyopathy, and gastrointestinal tract lesions. In absence of a vaccine, vector control and treatment of patients are the only tools to control the disease. Unfortunately, the only drugs now available for Chagas' disease, Nifurtimox and Benznidazole, are relatively toxic for adult patients, and require prolonged administration. Benznidazole is the first choice for Chagas disease treatment due to its lower side effects than Nifurtimox. However, different strategies are being sought to overcome Benznidazole's toxicity including shorter or intermittent administration schedules-either alone or in combination with other drugs. In addition, a long list of compounds has shown trypanocidal activity, ranging from natural products to specially designed molecules, re-purposing drugs commercialized to treat other maladies, and homeopathy. In the present review, we will briefly summarize the upturns of current treatment of Chagas disease, discuss the increment on research and scientific publications about this topic, and give an overview of the state-of-the-art research aiming to produce an alternative medication to treat T. cruzi infection

  17. Advanced prism-grating-prism imaging spectrograph in online industrial applications

    NASA Astrophysics Data System (ADS)

    Vaarala, Tapio; Aikio, Mauri; Keraenen, Heimo

    1997-08-01

    Imaging spectrographs have traditionally been utilized in aerial and remote sensing applications. A novel, compact and inexpensive imaging spectrograph developed by VTT Electronics is now available. It contains a multichannel fiber optic sensor head, a dispersive prism-grating-prism (PGP) component and digital CCD matrix camera capable of area integration. In rolled steel manufacturing, a protective oil film is applied on steel to resist corrosion while in transport and storage. The main problems in the oiling machine are film thickness control and jet failures. In this application, the spectrum of fluorescence of an oil film was measured simultaneously with parallel fibers. A relatively simple calibration and analysis procedure was used to calculate the oil film thickness. On-line color control for color reproduction is essential in both consumer and industrial products. The instrument was tested and analyzed for measuring differences in color by multivariate analysis of the spectra and by color space coordinate estimation. In general, a continuous spectrum is not absolute requirement. In these two examples, filter-based measurement would probably cost less thana PGP spectrograph solution. On the other hand, by measuring the spectrum and using an advanced signal processing algorithm one production version will cover all installations in both applications. In practice, only the fiber sensor mechanics need to be modified.

  18. PRISM3 Global Paleoclimate Reconstruction: A Global Warming Data Set

    NASA Astrophysics Data System (ADS)

    Dowsett, H. J.; Chandler, M. A.; Cronin, T. M.; Dwyer, G. S.; Haywood, A. M.; Hill, D. J.; Robinson, M. M.; Salzmann, U.; Williams, M.

    2007-12-01

    The Pliocene Research, Interpretation and Synoptic Mapping (PRISM) Project provides a conceptual model and synoptic view of the earth during the last interval considerably warmer than modern (3.3 to 3.0 Ma) through reconstruction of sea-surface temperature (SST) and other paleoenvironmental parameters. The first PRISM reconstruction, with its foundation in a global network of paleontological analyses, was completed in the early 1990s. Since then, several significant revisions have been released culminating in the PRISM2 data set. The primary goal of PRISM remains a better understanding of the Earth's climate system during the mid-Pliocene, and to that end, includes the development of digital data sets for use with climate models. The new PRISM3 reconstruction, slated to be released early in 2008, has revised SST fields based upon integration of previous and new faunal and floral analyses with new geochemical proxies and biomarkers, a revised vegetation/land cover data set utilizing the BIOME 4 vegetation classification scheme, 3-dimensional land ice distribution based upon ice-sheet model experiments, new sea level estimates based upon stable isotopes and bottom water temperatures, and revised sea-ice distribution. A deep ocean temperature reconstruction, PRISM3D, adds a 3- dimensional component, which can be used for initiating coupled ocean-atmosphere GCM simulations. PRISM3 is a collaborative effort between the U.S. Geological Survey (USGS), National Science Foundation (NSF), National Aeronautics and Space Administration (NASA), British Antarctic Survey (BAS), and several national and international academic institutions (Columbia University, Duke University, George Mason University, University of Leeds and University of Leicester).

  19. The response to prism deviations in human infants.

    PubMed

    Riddell, P M; Horwood, A M; Houston, S M; Turner, J E

    1999-09-23

    Previous research has suggested that infants are unable to make a corrective eye movement in response to a small base-out prism placed in front of one eye before 14-16 weeks [1]. Three hypotheses have been proposed to explain this early inability, and each of these makes different predictions for the time of onset of a response to a larger prism. The first proposes that infants have a 'degraded sensory capacity' and so require a larger retinal disparity (difference in the position of the image on the retina of each eye) to stimulate disparity detectors [2]. This predicts that infants might respond at an earlier age than previously reported [1] when tested using a larger prism. The second hypothesis proposes that infants learn to respond to larger retinal disparities through practice with small disparities [3]. According to this theory, using a larger prism will not result in developmentally earlier responses, and may even delay the response. The third hypothesis proposes that the ability to respond to prismatic deviation depends on maturational factors indicated by the onset of stereopsis (the ability to detect depth in an image on the basis of retinal disparity cues only) [4] [5], predicting that the size of the prism is irrelevant. To differentiate between these hypotheses, we tested 192 infants ranging from 2 to 52 weeks of age using a larger prism. Results showed that 63% of infants of 5-8 weeks of age produced a corrective eye movement in response to placement of a prism in front of the eye when in the dark. Both the percentage of infants who produced a response, and the speed of the response, increased with age. These results suggest that infants can make corrective eye movements in response to large prismatic deviations before 14-16 weeks of age. This, in combination with other recent results [6], discounts previous hypotheses.

  20. Type 1 electrocardiographic Brugada pattern in a woman with Chagas disease: a case report.

    PubMed

    Brito, Mitermayer R; Miranda, Carlos Eduardo S; Rabelo, Walter; Marino, Roberto L

    2010-09-01

    A 56-year-old woman with well-documented Chagas disease was found to have a spontaneous type 1 electrocardiographic (ECG) pattern of Brugada syndrome. It is most likely that this characteristic ST-segment elevation is an unusual manifestation of the pathological changes in Chagas disease. This ECG pattern has been found with other cardiac pathology and has been reported to be induced in patients with Chagas disease.

  1. Chagas Disease, Migration and Community Settlement Patterns in Arequipa, Peru

    PubMed Central

    Gilman, Robert H.; Cornejo del Carpio, Juan G.; Naquira, Cesar; Bern, Caryn; Levy, Michael Z.

    2009-01-01

    Background Chagas disease is one of the most important neglected tropical diseases in the Americas. Vectorborne transmission of Chagas disease has been historically rare in urban settings. However, in marginal communities near the city of Arequipa, Peru, urban transmission cycles have become established. We examined the history of migration and settlement patterns in these communities, and their connections to Chagas disease transmission. Methodology/Principal Findings This was a qualitative study that employed focus group discussions and in-depth interviews. Five focus groups and 50 in-depth interviews were carried out with 94 community members from three shantytowns and two traditional towns near Arequipa, Peru. Focus groups utilized participatory methodologies to explore the community's mobility patterns and the historical and current presence of triatomine vectors. In-depth interviews based on event history calendars explored participants' migration patterns and experience with Chagas disease and vectors. Focus group data were analyzed using participatory analysis methodologies, and interview data were coded and analyzed using a grounded theory approach. Entomologic data were provided by an ongoing vector control campaign. We found that migrants to shantytowns in Arequipa were unlikely to have brought triatomines to the city upon arrival. Frequent seasonal moves, however, took shantytown residents to valleys surrounding Arequipa where vectors are prevalent. In addition, the pattern of settlement of shantytowns and the practice of raising domestic animals by residents creates a favorable environment for vector proliferation and dispersal. Finally, we uncovered a phenomenon of population loss and replacement by low-income migrants in one traditional town, which created the human settlement pattern of a new shantytown within this traditional community. Conclusions/Significance The pattern of human migration is therefore an important underlying determinant of

  2. Study of dose calculation on breast brachytherapy using prism TPS

    NASA Astrophysics Data System (ADS)

    Fendriani, Yoza; Haryanto, Freddy

    2015-09-01

    PRISM is one of non-commercial Treatment Planning System (TPS) and is developed at the University of Washington. In Indonesia, many cancer hospitals use expensive commercial TPS. This study aims to investigate Prism TPS which been applied to the dose distribution of brachytherapy by taking into account the effect of source position and inhomogeneities. The results will be applicable for clinical Treatment Planning System. Dose calculation has been implemented for water phantom and CT scan images of breast cancer using point source and line source. This study used point source and line source and divided into two cases. On the first case, Ir-192 seed source is located at the center of treatment volume. On the second case, the source position is gradually changed. The dose calculation of every case performed on a homogeneous and inhomogeneous phantom with dimension 20 × 20 × 20 cm3. The inhomogeneous phantom has inhomogeneities volume 2 × 2 × 2 cm3. The results of dose calculations using PRISM TPS were compared to literature data. From the calculation of PRISM TPS, dose rates show good agreement with Plato TPS and other study as published by Ramdhani. No deviations greater than ±4% for all case. Dose calculation in inhomogeneous and homogenous cases show similar result. This results indicate that Prism TPS is good in dose calculation of brachytherapy but not sensitive for inhomogeneities. Thus, the dose calculation parameters developed in this study were found to be applicable for clinical treatment planning of brachytherapy.

  3. Prism adaptation changes the subjective proprioceptive localization of the hands.

    PubMed

    Scarpina, Federica; Van der Stigchel, Stefan; Nijboer, Tanja Cornelia Wilhelmina; Dijkerman, Hendrik Christiaan

    2015-03-01

    Prism adaptation involves a proprioceptive, a visual and a motor component. As the existing paradigms are not able to distinguish between these three components, the contribution of the proprioceptive component remains unclear. In the current study, a proprioceptive judgement task, in the absence of motor responses, was used to investigate how prism adaptation would specifically influences the felt position of the hands in healthy participants. The task was administered before and after adaptation to left and right displacing prisms using either the left or the right hand during the adaptation procedure. The results appeared to suggest that the prisms induced a drift in the felt position of the hands, although the after-effect depended on the combination of the pointing hand and the visual deviation induced by prisms. The results are interpreted as in line with the hypothesis of an asymmetrical neural architecture of somatosensory processing. Moreover, the passive proprioception of the hand position revealed different effects of proprioceptive re-alignment compared to active pointing straight ahead: different mechanisms about how visuo-proprioceptive discrepancy is resolved were hypothesized.

  4. Research on beam splitting prism in laser heterodyne interferometer

    NASA Astrophysics Data System (ADS)

    Fu, Xiu-hua; Xiong, Shi-fu; Kou, Yang; Pan, Yong-gang; Chen, Heng; Li, Zeng-yu; Zhang, Chuan-xin

    2014-08-01

    With the rapid development of optical testing technology, laser heterodyne interferometer has been used more and more widely. As the testing precision requirements continue to increase, the technical prism is an important component of heterodyne interference. The research utilizing thin film technology to improve optical performance of interferometer has been a new focus. In the article, based on the use requirements of interferometer beam splitting prism, select Ta2O5 and SiO2 as high and low refractive index materials respectively, deposit on substrate K9. With the help of TFCalc design software and Needle method, adopting electron gun evaporation and ion assisted deposition, the beam splitting prism is prepared successfully and the ratio of transmittance and reflectance for this beam splitting prism in 500~850 nm band, incident angle 45 degree is 8:2. After repeated tests, solved the difference problem of film deposition process parameters ,controlled thickness monitoring precision effectively and finally prepared the ideal beam splitting prism which is high adhesion and stable optics properties. The film the laser induced damage threshold and it meet the requirements of heterodyne interferometer for use.

  5. The Program for Regional and International Shorebird Monitoring (PRISM)

    USGS Publications Warehouse

    Bart, J.; Andres, B.; Brown, S.; Donaldson, G.; Harrington, B.; Johnston, V.; Jones, S.; Morrison, R.I.G.; Skagen, S.K.

    2005-01-01

    This report describes the a??Program for Regional and International Shorebird Monitoringa?? (PRISM). PRISM is being implemented by a Canada-United States Shorebird Monitoring and Assessment Committee formed in 2001 by the Canadian Shorebird Working Group and the U.S. Shorebird Council. PRISM provides a single blueprint for implementing the shorebird conservation plans recently completed in Canada and the United States. The goals of PRISM are to (1) estimate the size of breeding population of 74 shorebird taxa in North America; (2) describe the distribution, abundance, and habitat relationships for each of these taxa; (3) monitor trends in shorebird population size; (4) monitor shorebird numbers at stopover locations, and; (5) assist local managers in meeting their shorebird conservation goals. PRISM has four main components: arctic and boreal breeding surveys, temperate breeding surveys, temperate non-breeding surveys, and neotropical surveys. Progress on, and action items for, each major component are described. The more important major tasks for immediate action are carrying out the northern surveys, conducting regional analyses to design the program of migration counts, and evaluating aerial photographic surveys for migration and winter counts.

  6. Prism-based single-camera system for stereo display

    NASA Astrophysics Data System (ADS)

    Zhao, Yue; Cui, Xiaoyu; Wang, Zhiguo; Chen, Hongsheng; Fan, Heyu; Wu, Teresa

    2016-06-01

    This paper combines the prism and single camera and puts forward a method of stereo imaging with low cost. First of all, according to the principle of geometrical optics, we can deduce the relationship between the prism single-camera system and dual-camera system, and according to the principle of binocular vision we can deduce the relationship between binoculars and dual camera. Thus we can establish the relationship between the prism single-camera system and binoculars and get the positional relation of prism, camera, and object with the best effect of stereo display. Finally, using the active shutter stereo glasses of NVIDIA Company, we can realize the three-dimensional (3-D) display of the object. The experimental results show that the proposed approach can make use of the prism single-camera system to simulate the various observation manners of eyes. The stereo imaging system, which is designed by the method proposed by this paper, can restore the 3-D shape of the object being photographed factually.

  7. Genomes to natural products PRediction Informatics for Secondary Metabolomes (PRISM)

    PubMed Central

    Skinnider, Michael A.; Dejong, Chris A.; Rees, Philip N.; Johnston, Chad W.; Li, Haoxin; Webster, Andrew L. H.; Wyatt, Morgan A.; Magarvey, Nathan A.

    2015-01-01

    Microbial natural products are an invaluable source of evolved bioactive small molecules and pharmaceutical agents. Next-generation and metagenomic sequencing indicates untapped genomic potential, yet high rediscovery rates of known metabolites increasingly frustrate conventional natural product screening programs. New methods to connect biosynthetic gene clusters to novel chemical scaffolds are therefore critical to enable the targeted discovery of genetically encoded natural products. Here, we present PRISM, a computational resource for the identification of biosynthetic gene clusters, prediction of genetically encoded nonribosomal peptides and type I and II polyketides, and bio- and cheminformatic dereplication of known natural products. PRISM implements novel algorithms which render it uniquely capable of predicting type II polyketides, deoxygenated sugars, and starter units, making it a comprehensive genome-guided chemical structure prediction engine. A library of 57 tailoring reactions is leveraged for combinatorial scaffold library generation when multiple potential substrates are consistent with biosynthetic logic. We compare the accuracy of PRISM to existing genomic analysis platforms. PRISM is an open-source, user-friendly web application available at http://magarveylab.ca/prism/. PMID:26442528

  8. Dissecting slander and crying for justice: Carlos Chagas and the Nobel Prize of 1921.

    PubMed

    Bestetti, Reinaldo B; Cardinalli-Neto, Augusto

    2013-10-01

    Chagas disease was discovered by Carlos Chagas in 1909. Chagas worked at Oswaldo Cruz Institute, where the bases of experimental medicine were settled in Brazil, and that had no connection with the Faculty of Medicine of Rio de Janeiro. Chagas had several enemies at Oswaldo Cruz Institute mainly because of his election to Head of Service in 1910, and for the position of Oswaldo Cruz Directorship in 1917. Furthermore, Chagas gained enemies at Faculty of Medicine of Rio de Janeiro, which did not like to see the economical political autonomy of Oswaldo Cruz Institute. This allowed the Institute not only to perform top experimental research, but also to take the leadership of research in the country. Chagas was nominated to the Nobel Prize of 1921 in December, 1920. None was awarded the Nobel Prize in that year. He seems to have been evaluated by the Noble Committee of Karolinska Institute from March to May of 1921. At that time, his enemies were denying his discovery of Trypanosoma cruzi, a key point in Chagas' nomination by Karolinska Institute, and giving no epidemiological importance for the disease. By the same way, the obligation of small pox vaccination was tarnishing his public image. Having taken into account the epidemiologic importance of Chagas disease, the strong historical mistake in the process of Chagas evaluation, and the inequity behind all these facts, we insist on a posthumous Nobel Prize for the man who made the most complete medical-scientist discovery of all time.

  9. Dissecting slander and crying for justice: Carlos Chagas and the Nobel Prize of 1921.

    PubMed

    Bestetti, Reinaldo B; Cardinalli-Neto, Augusto

    2013-10-01

    Chagas disease was discovered by Carlos Chagas in 1909. Chagas worked at Oswaldo Cruz Institute, where the bases of experimental medicine were settled in Brazil, and that had no connection with the Faculty of Medicine of Rio de Janeiro. Chagas had several enemies at Oswaldo Cruz Institute mainly because of his election to Head of Service in 1910, and for the position of Oswaldo Cruz Directorship in 1917. Furthermore, Chagas gained enemies at Faculty of Medicine of Rio de Janeiro, which did not like to see the economical political autonomy of Oswaldo Cruz Institute. This allowed the Institute not only to perform top experimental research, but also to take the leadership of research in the country. Chagas was nominated to the Nobel Prize of 1921 in December, 1920. None was awarded the Nobel Prize in that year. He seems to have been evaluated by the Noble Committee of Karolinska Institute from March to May of 1921. At that time, his enemies were denying his discovery of Trypanosoma cruzi, a key point in Chagas' nomination by Karolinska Institute, and giving no epidemiological importance for the disease. By the same way, the obligation of small pox vaccination was tarnishing his public image. Having taken into account the epidemiologic importance of Chagas disease, the strong historical mistake in the process of Chagas evaluation, and the inequity behind all these facts, we insist on a posthumous Nobel Prize for the man who made the most complete medical-scientist discovery of all time. PMID:23410487

  10. Transmission of chagas disease (American trypanosomiasis) by food.

    PubMed

    Pereira, Karen Signori; Schmidt, Flávio Luis; Barbosa, Rodrigo L; Guaraldo, Ana M A; Franco, Regina M B; Dias, Viviane L; Passos, Luiz A C

    2010-01-01

    In April 2009, the centenary of the discovery of the American trypanosomiasis, or Chagas disease, was celebrated. A hundred years after the discovery, little has been invested in diagnostics and treatment because the disease affects mainly poor people in developing countries. However, some changes in the epidemiology of the disease are of great importance today. Chagas disease transmitted through food is a public health concern in all areas where there is a reservoir of Trypanosoma cruzi in wild animals (e.g., mammals and marsupials) and/or where infected triatomine bugs are in contact with human food source items (especially fruits and vegetables). Recently, several outbreaks of illness related to the ingestion of food contaminated with T. cruzi have been recorded in Brazil, Colombia, and Venezuela.

  11. Therapy of Chagas Disease: Implications for Levels of Prevention

    PubMed Central

    Sosa-Estani, Sergio; Colantonio, Lisandro; Segura, Elsa Leonor

    2012-01-01

    This paper reviews the evidence supporting the use of etiological treatment for Chagas disease that has changed the standard of care for patients with Trypanosoma cruzi infection in the last decades. Implications of this evidence on different levels of prevention as well as gaps in current knowledge are also discussed. In this regard, etiological treatment has shown to be beneficial as an intervention for secondary prevention to successfully cure the infection or to delay, reduce, or prevent the progression to disease, and as primary disease prevention by breaking the chain of transmission. Timely diagnosis during initial stages would allow for the prescription of appropriate therapies mainly in the primary health care system thus improving chances for a better quality of life. Based on current evidence, etiological treatment has to be considered as an essential public health strategy useful to reduce disease burden and to eliminate Chagas disease altogether. PMID:22523499

  12. [Representations, myths, and behaviors among Chagas disease patients with pacemakers].

    PubMed

    Magnani, Claudia; Oliveira, Bruna Guimarães; Gontijo, Eliane Dias

    2007-07-01

    This anthropological study aimed to evaluate the incorporation of pacemakers into the lives of individuals with Chagas disease. An ethnographic methodology was used, based on an open interview focusing on the personal perceptions of 15 patients with chronic Chagas cardiopathy who had required pacemaker implants at the Federal University Hospital in Belo Horizonte, Minas Gerais State, Brazil. As part of a broader quality of life analysis, the study investigated the cultural, physical, and psychological resources used by patients to confront, explain, and accept the disease process, including mental representations on the cultural perception of the illness and definition of social relations. The study was intended to contribute to comprehensive patient care by health professionals, including psychosocial aspects. Decoded and integrated orientation in the cultural sphere assumes an important role in order to prevent disinformation from perpetuating the dissemination of popular myths as active elements in patient stigmatization. PMID:17572811

  13. Enhanced scanning agility using a double pair of Risley prisms.

    PubMed

    Roy, Gilles; Cao, Xiaoying; Bernier, Robert; Roy, Simon

    2015-12-01

    Scanners with one pair of Risley prisms are robust and precise and they can be operated continuously. In this paper, we present a new scanner based on the use of two pairs of Risley prisms. The concept was driven by the need to add flexibility to Risley prism scanners used for lidar 3D mapping applications, while maintaining compactness and robustness. The first pair covers a FOV narrower than the second pair. The second pair is used to position the first Risley pair scan pattern anywhere within its own, larger, FOV. Doing so, it becomes possible, without additional scanner components, to increase the sampling point density at a specific location, to increase the sampling uniformity of the scanned area, and, while in motion, to maintain the sampling of a specific area of interest. PMID:26836680

  14. Interpretation of the Faust equation for a conventional refracting prism

    NASA Astrophysics Data System (ADS)

    Tewari, R. D.; Ghodgaonkar, A. M.; Gokhale, V. D.

    1995-10-01

    The Faust formula for a conventional refracting prism is interpreted in terms of the angle of incidence ( i1) and the angle of deviation (δ). Three new possibilities emerge, namely: (a) keeping the angle of incidence ( i1) constant and varying the angle of deviation (δ); (b) keeping the angle of deviation constant and varying the angle of incidence ( i1); (c) modification of the closed forms of Murty's expression and its equivalence to (b). Using paraxial approximation and keeping the angle of incidence ( i1) and angle of deviation (δ) constant we obtain a relation between the refractive index and the base length ( b) of a prism and, in principle, this is equivalent to the Marcuse variation for optical fibres. The condition for a Littrow prism, as well as for polarized radiation is derived. An expression to estimate the spectral bandwidth (SBW) of the instrument is also derived. Experimental values of refractive index at different wavelengths are within confidence limits.

  15. The PRISM4 (mid-Piacenzian) Palaeoenvironmental Reconstruction

    NASA Technical Reports Server (NTRS)

    Dowsett, Harry; Dolan, Aisling; Rowley, David; Moucha, Robert; Forte, Alessandro M.; Mitrovica, Jerry X.; Pound, Matthew; Salzmann, Ulrich; Robinson, Marci; Chandler, Mark; Foley, Kevin; Haywood, Alan

    2016-01-01

    The mid-Piacenzian is known as a period of relative warmth when compared to the present day. A comprehensive understanding of conditions during the Piacenzian serves as both a conceptual model and a source for boundary conditions as well as means of verification of global climate model experiments. In this paper we present the PRISM4 reconstruction, a paleoenvironmental reconstruction of the mid-Piacenzian (approximately 3 Ma) containing data for paleogeography, land and sea ice, sea-surface temperature, vegetation, soils, and lakes. Our retrodicted paleogeography takes into account glacial isostatic adjustments and changes in dynamic topography. Soils and lakes, both significant as land surface features, are introduced to the PRISM reconstruction for the first time. Sea-surface temperature and vegetation reconstructions are unchanged but now have confidence assessments. The PRISM4 reconstruction is being used as boundary condition data for the Pliocene Model Intercomparison Project Phase 2 (PlioMIP2) experiments.

  16. The PRISM4 (mid-Piacenzian) paleoenvironmental reconstruction

    NASA Astrophysics Data System (ADS)

    Dowsett, Harry; Dolan, Aisling; Rowley, David; Moucha, Robert; Forte, Alessandro M.; Mitrovica, Jerry X.; Pound, Matthew; Salzmann, Ulrich; Robinson, Marci; Chandler, Mark; Foley, Kevin; Haywood, Alan

    2016-07-01

    The mid-Piacenzian is known as a period of relative warmth when compared to the present day. A comprehensive understanding of conditions during the Piacenzian serves as both a conceptual model and a source for boundary conditions as well as means of verification of global climate model experiments. In this paper we present the PRISM4 reconstruction, a paleoenvironmental reconstruction of the mid-Piacenzian ( ˜ 3 Ma) containing data for paleogeography, land and sea ice, sea-surface temperature, vegetation, soils, and lakes. Our retrodicted paleogeography takes into account glacial isostatic adjustments and changes in dynamic topography. Soils and lakes, both significant as land surface features, are introduced to the PRISM reconstruction for the first time. Sea-surface temperature and vegetation reconstructions are unchanged but now have confidence assessments. The PRISM4 reconstruction is being used as boundary condition data for the Pliocene Model Intercomparison Project Phase 2 (PlioMIP2) experiments.

  17. Enhanced scanning agility using a double pair of Risley prisms.

    PubMed

    Roy, Gilles; Cao, Xiaoying; Bernier, Robert; Roy, Simon

    2015-12-01

    Scanners with one pair of Risley prisms are robust and precise and they can be operated continuously. In this paper, we present a new scanner based on the use of two pairs of Risley prisms. The concept was driven by the need to add flexibility to Risley prism scanners used for lidar 3D mapping applications, while maintaining compactness and robustness. The first pair covers a FOV narrower than the second pair. The second pair is used to position the first Risley pair scan pattern anywhere within its own, larger, FOV. Doing so, it becomes possible, without additional scanner components, to increase the sampling point density at a specific location, to increase the sampling uniformity of the scanned area, and, while in motion, to maintain the sampling of a specific area of interest.

  18. Quartz-Enhanced Photoacoustic Spectroscopy with Right-Angle Prism

    PubMed Central

    Liu, Yongning; Chang, Jun; Lian, Jie; Liu, Zhaojun; Wang, Qiang; Qin, Zengguang

    2016-01-01

    A right-angle prism was used to enhance the acoustic signal of a quartz-enhanced photoacoustic spectroscopy (QEPAS) system. The incident laser beam was parallelly inverted by the right-angle prism and passed through the gap between two tuning fork prongs again to produce another acoustic excitation. Correspondingly, two pairs of rigid metal tubes were used as acoustic resonators with resonance enhancement factors of 16 and 12, respectively. The QEPAS signal was enhanced by a factor of 22.4 compared with the original signal, which was acquired without resonators or a prism. In addition, the system noise was reduced a little with double resonators due to the Q factor decrease. The signal-to-noise ratio (SNR) was greatly improved. Additionally, a normalized noise equivalent absorption coefficient (NNEA) of 5.8 × 10−8 W·cm−1·Hz−1/2 was achieved for water vapor detection in the atmosphere. PMID:26861344

  19. The PRISM4 (mid-Piacenzian) paleoenvironmental reconstruction

    USGS Publications Warehouse

    Dowsett, Harry J.; Dolan, Aisling M.; Rowley, David; Moucha, Robert; Forte, Alessandro; Mitrovica, Jerry X.; Pound, Matthew; Salzmann, Ulrich; Robinson, Marci M.; Chandler, Mark; Foley, Kevin M.; Haywood, Alan M.

    2016-01-01

    The mid-Piacenzian is known as a period of relative warmth when compared to the present day. A comprehensive understanding of conditions during the Piacenzian serves as both a conceptual model and a source for boundary conditions as well as means of verification of global climate model experiments. In this paper we present the PRISM4 reconstruction, a paleoenvironmental reconstruction of the mid-Piacenzian ( ∼ 3 Ma) containing data for paleogeography, land and sea ice, sea-surface temperature, vegetation, soils, and lakes. Our retrodicted paleogeography takes into account glacial isostatic adjustments and changes in dynamic topography. Soils and lakes, both significant as land surface features, are introduced to the PRISM reconstruction for the first time. Sea-surface temperature and vegetation reconstructions are unchanged but now have confidence assessments. The PRISM4 reconstruction is being used as boundary condition data for the Pliocene Model Intercomparison Project Phase 2 (PlioMIP2) experiments.

  20. Cerebellar inactivation impairs memory of learned prism gaze-reach calibrations

    PubMed Central

    Hathaway, Emily N.; Taylor, Jordan A.; Thach, W. Thomas

    2011-01-01

    Three monkeys performed a visually guided reach-touch task with and without laterally displacing prisms. The prisms offset the normally aligned gaze/reach and subsequent touch. Naive monkeys showed adaptation, such that on repeated prism trials the gaze-reach angle widened and touches hit nearer the target. On the first subsequent no-prism trial the monkeys exhibited an aftereffect, such that the widened gaze-reach angle persisted and touches missed the target in the direction opposite that of initial prism-induced error. After 20–30 days of training, monkeys showed long-term learning and storage of the prism gaze-reach calibration: they switched between prism and no-prism and touched the target on the first trials without adaptation or aftereffect. Injections of lidocaine into posterolateral cerebellar cortex or muscimol or lidocaine into dentate nucleus temporarily inactivated these structures. Immediately after injections into cortex or dentate, reaches were displaced in the direction of prism-displaced gaze, but no-prism reaches were relatively unimpaired. There was little or no adaptation on the day of injection. On days after injection, there was no adaptation and both prism and no-prism reaches were horizontally, and often vertically, displaced. A single permanent lesion (kainic acid) in the lateral dentate nucleus of one monkey immediately impaired only the learned prism gaze-reach calibration and in subsequent days disrupted both learning and performance. This effect persisted for the 18 days of observation, with little or no adaptation. PMID:21389311

  1. Chagas Cardiomyopathy in the Context of the Chronic Disease Transition

    PubMed Central

    Hidron, Alicia I.; Gilman, Robert H.; Justiniano, Juan; Blackstock, Anna J.; LaFuente, Carlos; Selum, Walter; Calderon, Martiza; Verastegui, Manuela; Ferrufino, Lisbeth; Valencia, Eduardo; Tornheim, Jeffrey A.; O'Neal, Seth; Comer, Robert; Galdos-Cardenas, Gerson; Bern, Caryn

    2010-01-01

    Background Patients with Chagas disease have migrated to cities, where obesity, hypertension and other cardiac risk factors are common. Methodology/Principal Findings The study included adult patients evaluated by the cardiology service in a public hospital in Santa Cruz, Bolivia. Data included risk factors for T. cruzi infection, medical history, physical examination, electrocardiogram, echocardiogram, and contact 9 months after initial data collection to ascertain mortality. Serology and PCR for Trypanosoma cruzi were performed. Of 394 participants, 251 (64%) had confirmed T. cruzi infection by serology. Among seropositive participants, 109 (43%) had positive results by conventional PCR; of these, 89 (82%) also had positive results by real time PCR. There was a high prevalence of hypertension (64%) and overweight (body mass index [BMI] >25; 67%), with no difference by T. cruzi infection status. Nearly 60% of symptomatic congestive heart failure was attributed to Chagas cardiomyopathy; mortality was also higher for seropositive than seronegative patients (p = 0.05). In multivariable models, longer residence in an endemic province, residence in a rural area and poor housing conditions were associated with T. cruzi infection. Male sex, increasing age and poor housing were independent predictors of Chagas cardiomyopathy severity. Males and participants with BMI ≤25 had significantly higher likelihood of positive PCR results compared to females or overweight participants. Conclusions Chagas cardiomyopathy remains an important cause of congestive heart failure in this hospital population, and should be evaluated in the context of the epidemiological transition that has increased risk of obesity, hypertension and chronic cardiovascular disease. PMID:20502520

  2. Economic evaluation of Chagas disease screening in Spain.

    PubMed

    Imaz-Iglesia, Iñaki; Miguel, Lucía García-San; Ayala-Morillas, L Eduardo; García-Pérez, Lidia; González-Enríquez, Jesús; Blasco-Hernández, Teresa; Martín-Águeda, María Belén; Sarría-Santamera, Antonio

    2015-08-01

    Although Spain is the European country with the highest Chagas disease burden, the country does not have a national control program of the disease. The purpose of this study is to evaluate the efficiency of several strategies for Chagas disease screening among Latin American residents living in Spain. The following screening strategies were evaluated: (1) non-screening; (2) screening of the Latin American pregnant women and their newborns; (3) screening also the relatives of the positive pregnant women; (4) screening also the relatives of the negative pregnant women. A cost-utility analysis was carried out to compare the four strategies from two perspectives, the societal and the Spanish National Health System (SNHS). A decision tree representing the clinical evolution of Chagas disease throughout patient's life was built. The strategies were compared through the incremental cost-utility ratio, using euros as cost measurement and quality-adjusted life years as utility measurement. A sensitivity analysis was performed to test the model parameters and their influence on the results. We found the "Non-screening" as the most expensive and less effective of the evaluated strategies, from both the societal and the SNHS perspectives. Among the screening evaluated strategies the most efficient was, from both perspectives, to extent the antenatal screening of the Latin American pregnant women and their newborns up to the relatives of the positive women. Several parameters influenced significantly on the sensitivity analyses, particularly the chronic treatment efficacy or the prevalence of Chagas disease. In conclusion, for the general Latin American immigrants living in Spain the most efficient would be to screen the Latin American mothers, their newborns and the close relatives of the mothers with a positive serology. However for higher prevalence immigrant population the most efficient intervention would be to extend the program to the close relatives of the negative

  3. Challenges and perspectives of Chagas disease: a review

    PubMed Central

    2013-01-01

    Chagas disease (CD), also known as American trypanosomiasis, is caused by the flagellated protozoan Trypanosoma cruzi, and affects an estimated 8 to 10 million people worldwide. In Latin America, 25 million people live in risk areas, while in 2008 alone, 10,000 CD-related deaths were reported. This review aimed to evaluate the challenges of CD control, future perspectives, and actions performed worldwide to control expansion of the disease and its impact on public health in Latin America. PMID:24354455

  4. Prophylactic and therapeutic DNA vaccines against Chagas disease.

    PubMed

    Arce-Fonseca, Minerva; Rios-Castro, Martha; Carrillo-Sánchez, Silvia del Carmen; Martínez-Cruz, Mariana; Rodríguez-Morales, Olivia

    2015-01-01

    Chagas disease is a zoonosis caused by Trypanosoma cruzi in which the most affected organ is the heart. Conventional chemotherapy has a very low effectiveness; despite recent efforts, there is currently no better or more effective treatment available. DNA vaccines provide a new alternative for both prevention and treatment of a variety of infectious disorders, including Chagas disease. Recombinant DNA technology has allowed some vaccines to be developed using recombinant proteins or virus-like particles capable of inducing both a humoral and cellular specific immune response. This type of immunization has been successfully used in preclinical studies and there are diverse models for viral, bacterial and/or parasitic diseases, allergies, tumors and other diseases. Therefore, several research groups have been given the task of designing a DNA vaccine against experimental infection with T. cruzi. In this review we explain what DNA vaccines are and the most recent studies that have been done to develop them with prophylactic or therapeutic purposes against Chagas disease.

  5. The Epidemiology, Clinical Manifestations, and Management of Chagas Heart Disease.

    PubMed

    Malik, Lindsey H; Singh, Gagan D; Amsterdam, Ezra A

    2015-09-01

    Chagas disease results from infection by the protozoan parasite Trypanosoma cruzi and is endemic in Latin America. T cruzi is most commonly transmitted through the feces of an infected triatomine, but can also be congenital, via contaminated blood transfusion or through direct oral contact. In the acute phase, the disease can cause cardiac derangements such as myocarditis, conduction system abnormalities, and/or pericarditis. If left untreated, the disease advances to the chronic phase. Up to one-half of these patients will develop a cardiomyopathy, which can lead to cardiac failure and/or ventricular arrhythmias, both of which are major causes of mortality. Diagnosis is confirmed by serologic testing for specific immunoglobulin G antibodies. Initial treatment consists of the antiparasitic agents benznidazole and nifurtimox. The treatment of Chagas cardiac disease comprises standard medical therapy for heart failure and amiodarone for ventricular arrhythmias, with consideration for implantable cardioverter-defibrillator. Chagas disease causes the highest infectious burden of any parasitic disease in the Western Hemisphere, and increased awareness of this disease is essential to improve diagnosis, enhance management, and reduce spread.

  6. Trypanosoma cruzi and Chagas' Disease in the United States

    PubMed Central

    Bern, Caryn; Kjos, Sonia; Yabsley, Michael J.; Montgomery, Susan P.

    2011-01-01

    Summary: Chagas' disease is caused by the protozoan parasite Trypanosoma cruzi and causes potentially life-threatening disease of the heart and gastrointestinal tract. The southern half of the United States contains enzootic cycles of T. cruzi, involving 11 recognized triatomine vector species. The greatest vector diversity and density occur in the western United States, where woodrats are the most common reservoir; other rodents, raccoons, skunks, and coyotes are also infected with T. cruzi. In the eastern United States, the prevalence of T. cruzi is highest in raccoons, opossums, armadillos, and skunks. A total of 7 autochthonous vector-borne human infections have been reported in Texas, California, Tennessee, and Louisiana; many others are thought to go unrecognized. Nevertheless, most T. cruzi-infected individuals in the United States are immigrants from areas of endemicity in Latin America. Seven transfusion-associated and 6 organ donor-derived T. cruzi infections have been documented in the United States and Canada. As improved control of vector- and blood-borne T. cruzi transmission decreases the burden in countries where the disease is historically endemic and imported Chagas' disease is increasingly recognized outside Latin America, the United States can play an important role in addressing the altered epidemiology of Chagas' disease in the 21st century. PMID:21976603

  7. Methodological advances in drug discovery for Chagas disease

    PubMed Central

    Bustamante, Juan M.; Tarleton, Rick L.

    2011-01-01

    Introduction Chagas disease is the highest impact human infectious disease in Latin America, and the leading worldwide cause of myocarditis. Despite the availability of several compounds that have demonstrated efficacy in limiting the effects of T. cruzi, these compounds are rarely used due to their variable efficacy, substantial side effects and the lack of methodologies for confirming their effectiveness. Furthermore, the development of more efficacious compounds is challenged by limitations of systems for assessing drug efficacy in vitro and in vivo. Areas covered Herein, the authors review the development of Chagas disease drug discovery methodology, focusing on recent developments in high throughput screening, in vivo testing methods and assessments of efficacy in humans. Particularly, this review documents the significant progress that has taken place over the last 5 years that have paved the way for both target-focused and high-throughput screens of compound libraries. Expert opinion The tools for in vitro and in vivo screening of anti-T. cruzi compounds have improved dramatically in the last few years and there are now a number of excellent in vivo testing models available; this somewhat alleviates the bottleneck issue of quickly and definitively demonstrating in vivo efficacy in a relevant host animal system. These advances emphasize the potential for additional progress resulting in new treatments for Chagas disease in the coming years. That being said, national and international agencies must improve the coordination of research and development efforts in addition to cultivating the funding sources for the development of these new treatments. PMID:21712965

  8. Novel cruzipain inhibitors for the chemotherapy of chronic Chagas disease.

    PubMed

    Sbaraglini, María L; Bellera, Carolina L; Fraccaroli, Laura; Larocca, Luciana; Carrillo, Carolina; Talevi, Alan; Alba Soto, Catalina D

    2016-07-01

    Despite current efforts worldwide to develop new medications against Chagas disease, only two drugs are available, nifurtimox and benznidazole. Both drugs require prolonged treatment and have multiple side effects and limited efficacy on adult patients chronically infected with Trypanosoma cruzi. Recently, computer-guided drug repositioning led to the discovery of the trypanocidal effects of clofazimine and benidipine. These compounds showed inhibitory effects on cruzipain, the major cysteine protease of T. cruzi, of different parasite stages and in a murine model of acute Chagas disease. The aim of this work was to determine the efficacy of these novel cruzipain inhibitors when administered in a murine model of chronic Chagas disease. Benidipine and clofazimine were able to reduce the parasite burden in cardiac and skeletal muscles of chronically infected mice compared with untreated mice as well as diminish the inflammatory process in these tissues. Further studies should be performed to study the synergism with benznidazole and nifurtimox in view of combined therapies. PMID:27216381

  9. A case of Chagas' disease panniculitis after kidney transplantation.

    PubMed

    Campos, Fábio Prestes de; Pansard, Henry Mor; Arantes, Luiz Cláudio; Rodrigues, Arnaldo Teixeira; Daubermann, Melissa Falster; Azambuja, Marcos Felipe; Argenta, Laércio Cassol; Silva, Luiz Alberto Michet da

    2016-03-01

    Chagas' disease carries high morbidity and mortality due to acute parasitemia or cardiac, digestive, cutaneous or neurologic chronic lesions. Latin American countries have the majority of infected or at risk people. Transplanted patients using immunosuppressive agents may develop severe and even fatal forms of the disease. The available treatment causes frequent severe side-effects. A 59 years-old woman with end stage renal disease and positive serology for Chagas` disease, but without any clinical manifestation of this pathology, underwent kidney transplantation from a cadaveric donor and displayed three months later a thigh panniculitis from which a biopsy unveiled amastigote forms of Trypanosoma cruzi. The skin lesions disappeared following treatment with benzonidazole, but the drug was discontinued due to severe pancytopenia. Along with this, infection with E. faecalis and cytomegalovirus were treated with vancomicin and ganciclovir. The patient kept very well afterwards, with no new skin lesions and with good graft function. One year and three months after the transplant, she had an emergency surgery for an aortic dissecting aneurysm. Irreversible shock and death occurred in the immediate post-surgical period. It was not possible to establish or to rule out a relationship between the trypanosomiasis and the aortic lesions. Chagas` disease must be remembered in differential diagnosis of several clinical situations in transplant patients, mainly in endemic areas. The treatment can yeld good clinical response, but serious side-effects from the drugs may ensue. More effective and better tolerated options are in need for treatment or prophylaxis. PMID:27049374

  10. Opportunity Cost for Early Treatment of Chagas Disease in Mexico

    PubMed Central

    Ramsey, Janine M.; Elizondo-Cano, Miguel; Sanchez-González, Gilberto; Peña-Nieves, Adriana; Figueroa-Lara, Alejandro

    2014-01-01

    Background Given current neglect for Chagas disease in public health programs in Mexico, future healthcare and economic development policies will need a more robust model to analyze costs and impacts of timely clinical attention of infected populations. Methodology/Principal Findings A Markov decision model was constructed to simulate the natural history of a Chagas disease cohort in Mexico and to project the associated short and long-term clinical outcomes and corresponding costs. The lifetime cost for a timely diagnosed and treated Chagas disease patient is US$ 10,160, while the cost for an undiagnosed individual is US$ 11,877. The cost of a diagnosed and treated case increases 24-fold from early acute to indeterminate stage. The major cost component for lifetime cost was working days lost, between 44% and 75%, depending on the program scenario for timely diagnosis and treatment. Conclusions/Significance In the long term, it is cheaper to diagnose and treat chagasic patients early, instead of doing nothing. This finding by itself argues for the need to shift current policy, in order to prioritize and attend this neglected disease for the benefit of social and economic development, which implies including treatment drugs in the national formularies. Present results are even more relevant, if one considers that timely diagnosis and treatment can arrest clinical progression and enhance a chronic patient's quality of life. PMID:24743112

  11. The Role of Haptoglobin Genotypes in Chagas Disease

    PubMed Central

    Mundaray Fernández, Ninomar; Fernández-Mestre, Mercedes

    2014-01-01

    Although the number of people infected with T. cruzi is on the rise, host genetic and immune components that are crucial in the development of the Chagas disease have been discovered. We investigated the frequency of polymorphisms in the gene encoding haptoglobin of patients with chronic Chagas disease. The results suggest that while the HP1-1 genotype may confer protection against infection and the development of chronic Chagas disease due to the rapid metabolism of the Hp1-1-Hb complex and its anti-inflammatory activity, the presence of HP2-2 genotype may increase susceptibility towards a chronic condition of the disease due to a slow metabolism of the Hp2-2-Hb complex, lower antioxidant activity, and increased inflammatory reactivity, which lead to cell damage and a deterioration of the cardiac function. Finally, correlations between HP genotypes in different age groups and cardiac manifestations suggest that HP polymorphism could influence the prognosis of this infectious disease. This study shows some of the relevant aspects of the haptoglobin gene polymorphism and its implications in the T. cruzi infection. PMID:25147423

  12. Scrutinizing the Biomarkers for the Neglected Chagas Disease: How Remarkable!

    PubMed Central

    Pinho, Rosa T.; Waghabi, Mariana C.; Cardillo, Fabíola; Mengel, José; Antas, Paulo R. Z.

    2016-01-01

    Biomarkers or biosignature profiles have become accessible over time in population-based studies for Chagas disease. Thus, the identification of consistent and reliable indicators of the diagnosis and prognosis of patients with heart failure might facilitate the prioritization of therapeutic management to those with the highest chance of contracting this disease. The purpose of this paper is to review the recent state and the upcoming trends in biomarkers for human Chagas disease. As an emerging concept, we propose a classification of biomarkers based on plasmatic-, phenotype-, antigenic-, genetic-, and management-related candidates. The available data revisited here reveal the lessons learned thus far and the existing challenges that still lie ahead to enable biomarkers to be employed consistently in risk evaluation for this disease. There is a strong need for biomarker validation, particularly for biomarkers that are specific to the clinical forms of Chagas disease. The current failure to achieve the eradication of the transmission of this disease has produced determination to solve this validation issue. Finally, it would be strategic to develop a wide variety of biomarkers and to test them in both preclinical and clinical trials. PMID:27563302

  13. Kaleidoscope modes in large aperture Porro prism resonators.

    PubMed

    Burger, Liesl; Forbes, Andrew

    2008-08-18

    We apply a new method of modeling Porro prism resonators, using the concept of rotating loss screens, to study stable and unstable Porro prism resonator. We show that the previously observed petal--like modal output is in fact only the lowest order mode, and reveal that a variety of kaleidoscope beam modes will be produced by these resonators when the intra--cavity apertures are sufficiently large to allow higher order modes to oscillate. We also show that only stable resonators will produce these modes. PMID:18711509

  14. Imaging of neuronal tissue using a prism adjunct

    NASA Astrophysics Data System (ADS)

    Broadbridge, Philip; Bradu, Adrian; Lall, Gurprit; Podoleanu, Adrian G.

    2014-03-01

    We present the use of a prism as an imaging adjunct with a multimodal system of optical coherence tomography and confocal microscopy operating at 1320 nm and 970 nm respectively. A comparison is performed between en-face OCT images acquired using the system and cross section OCT images obtained through a prism inserted into neuronal tissue of an intact ex-vivo murine brain. The en-face images and cross section images are scans of the same area; however each method has shown different aspects, allowing for greater interpretation of the neuronal tissue.

  15. Beam distortion of rotation double prisms with an arbitrary incident angle.

    PubMed

    Li, Anhu; Zuo, Qiyou; Sun, Wansong; Yi, Wanli

    2016-07-01

    The distortion of beam shape in rotation Risley prisms is discussed in this paper. Using the ray-tracing method based on vector refraction theorem, a rigorous theoretical model of beam distortion with an arbitrary incident angle is established to explore the influencing factors. For a specified double-prism pair, the emergent beam is squeezed in one direction while stretched in the mutual perpendicular direction, the distortion of which is determined by the relative rotation angle. Moreover, the distortion of beam shape is greatly influenced by the wedge angles and the refractive indices of the prisms, as well as different double-prism configurations, while uncorrelated to the prism thickness and the distance between two prisms. This paper demonstrates the regular change of the beam shape with multiparameter variations in rotation double prisms, which can be applied to the design of rotation double-prism systems. PMID:27409205

  16. Beam distortion of rotation double prisms with an arbitrary incident angle.

    PubMed

    Li, Anhu; Zuo, Qiyou; Sun, Wansong; Yi, Wanli

    2016-07-01

    The distortion of beam shape in rotation Risley prisms is discussed in this paper. Using the ray-tracing method based on vector refraction theorem, a rigorous theoretical model of beam distortion with an arbitrary incident angle is established to explore the influencing factors. For a specified double-prism pair, the emergent beam is squeezed in one direction while stretched in the mutual perpendicular direction, the distortion of which is determined by the relative rotation angle. Moreover, the distortion of beam shape is greatly influenced by the wedge angles and the refractive indices of the prisms, as well as different double-prism configurations, while uncorrelated to the prism thickness and the distance between two prisms. This paper demonstrates the regular change of the beam shape with multiparameter variations in rotation double prisms, which can be applied to the design of rotation double-prism systems.

  17. Benznidazole Shortage Makes Chagas Disease a Neglected Tropical Disease in Developed Countries: Data from Spain

    PubMed Central

    Navarro, Miriam; Norman, Francesca F.; Pérez-Molina, José Antonio; López-Vélez, Rogelio

    2012-01-01

    Chagas disease is a neglected tropical disease endemic in Latin America. The first-line treatment option is benznidazole, but stocks are expected to run out in the coming months. Spain would need around 5 million benznidazole tablets. This drug shortage could make Chagas disease a neglected tropical disease also in developed countries. PMID:22826485

  18. Chagas Disease Screening in Maternal Donors of Publicly Banked Umbilical Cord Blood, United States.

    PubMed

    Edwards, James M; Gilner, Jennifer B; Hernandez, Jose; Kurtzberg, Joanne; Heine, R Phillips

    2016-08-01

    To assess patterns of Chagas disease, we reviewed results of screening umbilical cord blood from a US public cord blood bank during 2007-2014. Nineteen maternal donors tested positive for Trypanosoma cruzi parasites (0.04%). Because perinatal transmission of Chagas disease is associated with substantial illness, targeted prenatal programs should screen for this disease. PMID:27433974

  19. Chagas Disease Screening in Maternal Donors of Publicly Banked Umbilical Cord Blood, United States

    PubMed Central

    Gilner, Jennifer B.; Hernandez, Jose; Kurtzberg, Joanne; Heine, R. Phillips

    2016-01-01

    To assess patterns of Chagas disease, we reviewed results of screening umbilical cord blood from a US public cord blood bank during 2007–2014. Nineteen maternal donors tested positive for Trypanosoma cruzi parasites (0.04%). Because perinatal transmission of Chagas disease is associated with substantial illness, targeted prenatal programs should screen for this disease. PMID:27433974

  20. Simple Method For Testing Of The 90° Angle Of A Reflecting Prism

    NASA Astrophysics Data System (ADS)

    Ghodgaonkar, A. M.; Tiwari, R. D.; Ramani, K.

    1982-12-01

    A simple method for testing the 90° angle of a reflecting prism by placing two prisms in contact with one another on a standard test plate and counting the number of fringes is outlined. An angle accuracy of less than a second for the angle of a 90° reflecting prism has been obtained.

  1. 49 CFR 390.203 - PRISM State registration/biennial updates.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 5 2014-10-01 2014-10-01 false PRISM State registration/biennial updates. 390.203... FEDERAL MOTOR CARRIER SAFETY REGULATIONS; GENERAL Unified Registration System § 390.203 PRISM State... the Performance and Registration Information Systems Management (PRISM) program (authorized...

  2. 49 CFR 390.203 - PRISM State registration/biennial updates.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 5 2013-10-01 2013-10-01 false PRISM State registration/biennial updates. 390.203... FEDERAL MOTOR CARRIER SAFETY REGULATIONS; GENERAL Unified Registration System § 390.203 PRISM State... the Performance and Registration Information Systems Management (PRISM) program (authorized...

  3. Synthesis and photocatalytic activity of porous bismuth oxychloride hexagonal prisms.

    PubMed

    Ding, Liyong; Chen, Huan; Wang, Qingqian; Zhou, Tengfei; Jiang, Qingqing; Yuan, Yuhong; Li, Jinlin; Hu, Juncheng

    2016-01-18

    Porous BiOCl hexagonal prisms have been successfully prepared through a simple solvothermal route. These novel BiOCl HPs with porous structures are assembled from nanoparticles and exhibit high activity and selectivity toward the photocatalytic aerobic oxidation of benzyl alcohol to benzaldehyde and degradation of methyl orange. PMID:26592759

  4. Design of airborne imaging spectrometer based on curved prism

    NASA Astrophysics Data System (ADS)

    Nie, Yunfeng; Xiangli, Bin; Zhou, Jinsong; Wei, Xiaoxiao

    2011-11-01

    A novel moderate-resolution imaging spectrometer spreading from visible wavelength to near infrared wavelength range with a spectral resolution of 10 nm, which combines curved prisms with the Offner configuration, is introduced. Compared to conventional imaging spectrometers based on dispersive prism or diffractive grating, this design possesses characteristics of small size, compact structure, low mass as well as little spectral line curve (smile) and spectral band curve (keystone or frown). Besides, the usage of compound curved prisms with two or more different materials can greatly reduce the nonlinearity inevitably brought by prismatic dispersion. The utilization ratio of light radiation is much higher than imaging spectrometer of the same type based on combination of diffractive grating and concentric optics. In this paper, the Seidel aberration theory of curved prism and the optical principles of Offner configuration are illuminated firstly. Then the optical design layout of the spectrometer is presented, and the performance evaluation of this design, including spot diagram and MTF, is analyzed. To step further, several types of telescope matching this system are provided. This work provides an innovational perspective upon optical system design of airborne spectral imagers; therefore, it can offer theoretic guide for imaging spectrometer of the same kind.

  5. Liquid-crystal prisms for tip-tilt adaptive optics.

    PubMed

    Love, G D; Major, J V; Purvis, A

    1994-08-01

    Results from an electrically addressed liquid-crystal cell producing continuous phase profiles are presented. The adaptive deflection of a beam of light for use in a tip-tilt adaptive optics system is demonstrated. We compare the optical performance of liquid-crystal prisms with experimental data on atmospheric seeing at the William Herschel Telescope.

  6. A Precision Variable, Double Prism Attenuator for CO(2) Lasers.

    PubMed

    Oseki, T; Saito, S

    1971-01-01

    A precision, double prism attenuator for CO(2) lasers, calibrated by its gap capacitance, was constructed to evaluate its possible use as a standard for attenuation measurements. It was found that the accuracy was about 0.1 dB with a dynamic range of about 40 dB.

  7. Liquid-crystal prisms for tip-tilt adaptive optics.

    PubMed

    Love, G D; Major, J V; Purvis, A

    1994-08-01

    Results from an electrically addressed liquid-crystal cell producing continuous phase profiles are presented. The adaptive deflection of a beam of light for use in a tip-tilt adaptive optics system is demonstrated. We compare the optical performance of liquid-crystal prisms with experimental data on atmospheric seeing at the William Herschel Telescope. PMID:19844566

  8. The Portable Remote Imaging Spectrometer (PRISM) Coastal Ocean Sensor

    NASA Technical Reports Server (NTRS)

    Mouroulis, Pantazis; VanGorp, Byron E.; Green, Robert O.; Eastwppd, Michael; Wilson, Daniel W.; Richardson, Brandon; Dierssen, Heidi

    2012-01-01

    PRISM is an airborne pushbroom imaging spectrometer intended to address the needs of airborne coastal ocean science research. Its critical characteristics are high throughput and signal-to-noise ratio, high uniformity of response to reduce spectral artifacts, and low polarization sensitivity. We give a brief overview of the instrument and results from laboratory calibration measurements regarding the spatial, spectral, radiometric and polarization characteristics.

  9. Portable Remote Imaging Spectrometer (PRISM): Laboratory and Field Calibration

    NASA Technical Reports Server (NTRS)

    Mouroulis, Pantazis; Van Gorp, Byron; Green, Robert O.; Eastwood, Michael; Boardman, Joseph; Richardson, Brandon S.; Rodriguez, Jose I.; Urquiza, Eugenio; Franklin, Brian D.; Gao, Bo-Cai

    2012-01-01

    We report the characteristics of the Portable Remote Imaging Spectrometer, an airborne sensor specifically designed for the challenges of coastal ocean research. PRISM has high signal to noise ratio and uniformity, as well as low polarization sensitivity. Acquisition of high quality data has been demonstrated with the first engineering flight.

  10. Cardiac rate detection method based on the beam splitter prism

    NASA Astrophysics Data System (ADS)

    Yang, Lei; Liu, Xiaohua; Liu, Ming; Zhao, Yuejin; Dong, Liquan; Zhao, Ruirui; Jin, Xiaoli; Zhao, Jingsheng

    2013-09-01

    A new cardiac rate measurement method is proposed. Through the beam splitter prism, the common-path optical system of transmitting and receiving signals is achieved. By the focusing effect of the lens, the small amplitude motion artifact is inhibited and the signal-to-noise is improved. The cardiac rate is obtained based on the PhotoPlethysmoGraphy (PPG). We use LED as the light source and use photoelectric diode as the receiving tube. The LED and the photoelectric diode are on the different sides of the beam splitter prism and they form the optical system. The signal processing and display unit is composed by the signal processing circuit, data acquisition device and computer. The light emitted by the modulated LED is collimated by the lens and irradiates the measurement target through the beam splitter prism. The light reflected by the target is focused on the receiving tube through the beam splitter prism and another lens. The signal received by the photoelectric diode is processed by the analog circuit and obtained by the data acquisition device. Through the filtering and Fast Fourier Transform, the cardiac rate is achieved. We get the real time cardiac rate by the moving average method. We experiment with 30 volunteers, containing different genders and different ages. We compare the signals captured by this method to a conventional PPG signal captured concurrently from a finger. The results of the experiments are all relatively agreeable and the biggest deviation value is about 2bmp.

  11. 2. GENERAL VIEW ACROSS CANAL PRISM TO TOWPATH BERM SOUTH ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. GENERAL VIEW ACROSS CANAL PRISM TO TOWPATH BERM SOUTH OF THE SPILLWAY; VIEW TO SOUTHWEST FROM ROUTE 146 EMBANKMENT. - Blackstone Canal Millbury Segment, Beginning northwest of State Route 146 & McCracken Road, running along west side of Route 146, Millbury, Worcester County, MA

  12. 4. VIEW SOUTH SHOWING AQUEDUCT PRISM. NOTE 1920 TIMBER AND ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    4. VIEW SOUTH SHOWING AQUEDUCT PRISM. NOTE 1920 TIMBER AND CONCRETE FLOORING SYSTEM, POCKETS FOR VERTICAL POSTS AND BRIDGING, STEEL BRACES ADDED BY THE NATIONAL PARK SERVICE CIRCA 1962. - Chesapeake & Ohio Canal, Conococheague Creek Aqueduct, Milepost 99.80, Williamsport, Washington County, MD

  13. 3. VIEW SOUTH SHOWING AQUEDUCT PRISM. NOTE 1920 TIMBER AND ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    3. VIEW SOUTH SHOWING AQUEDUCT PRISM. NOTE 1920 TIMBER AND CONCRETE FLOORING SYSTEM, CUT STONE FACE OF PARAPET WALL, AND WROUGHT IRON BOLTS USED TO SECURE THE RUBBING RAIL. - Chesapeake & Ohio Canal, Conococheague Creek Aqueduct, Milepost 99.80, Williamsport, Washington County, MD

  14. 3. GENERAL VIEW ACROSS CANAL PRISM TO TOWPATH BERM NORTH ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    3. GENERAL VIEW ACROSS CANAL PRISM TO TOWPATH BERM NORTH OF THE SPILLWAY; VIEW TO WEST FROM ROUTE 146 EMBANKMENT. - Blackstone Canal Millbury Segment, Beginning northwest of State Route 146 & McCracken Road, running along west side of Route 146, Millbury, Worcester County, MA

  15. Budding Architects: Exploring the Designs of Pyramids and Prisms

    ERIC Educational Resources Information Center

    Leavy, Aisling; Hourigan, Mairéad

    2015-01-01

    The context of students as architects is used to examine the similarities and differences between prisms and pyramids. Leavy and Hourigan use the Van Hiele Model as a tool to support teachers to develop expectations for differentiating geometry in the classroom using practical examples.

  16. Simulation of electrically controlled nematic liquid crystal Rochon prism

    NASA Astrophysics Data System (ADS)

    Buczkowska, M.; Derfel, G.

    2016-09-01

    Operation of an electrically controlled beam steering device based on Rochon prism made by use of nematic liquid crystal is modelled numerically. Deflection angles and angular distribution of light intensity in the deflected beam are calculated. Dynamics of the device is studied. Advantage of application of dual frequency nematic liquid crystal is demonstrated. Role of flexoelectric properties of the nematic is analyzed.

  17. The Pacific Oaks College's Prism Principles Professional Development Approach

    ERIC Educational Resources Information Center

    Beyer, Kalani

    2012-01-01

    In a struggling atmosphere for education, one college is optimistic about the future by offering school districts its PRISM Principles professional development as a means to ensure that "no child is left behind." Pacific Oaks College & Children's School is known for its premiere programs in early childhood education, human…

  18. Synthesis and photocatalytic activity of porous bismuth oxychloride hexagonal prisms.

    PubMed

    Ding, Liyong; Chen, Huan; Wang, Qingqian; Zhou, Tengfei; Jiang, Qingqing; Yuan, Yuhong; Li, Jinlin; Hu, Juncheng

    2016-01-18

    Porous BiOCl hexagonal prisms have been successfully prepared through a simple solvothermal route. These novel BiOCl HPs with porous structures are assembled from nanoparticles and exhibit high activity and selectivity toward the photocatalytic aerobic oxidation of benzyl alcohol to benzaldehyde and degradation of methyl orange.

  19. Compact prisms for polarisation splitting of fibre laser beams

    SciTech Connect

    Davydov, B L; Yagodkin, D I

    2005-11-30

    Simple compact monoprisms for spatial splitting of polarised laser beams with relatively small diameters (no more than 1 mm) are considered. Prisms can be made of optically inactive CaCO{sub 3}, {alpha}-BaB{sub 2}O{sub 4} ({alpha}-BBO), LiIO{sub 3}, LiNbO{sub 3}, YVO{sub 4}, and TiO{sub 2} crystals known in polarisation optics. The exact solution of the Snell equation for the extraordinary wave reflected from a surface arbitrarily tilted to its wave vector is obtained. The analysis of variants of the solution allows the fabrication of prisms with any deviation angles of the extraordinary wave by preserving the propagation direction of the ordinary wave. Three variants of prisms are considered: with minimised dimensions, with the Brewster output of the extraordinary beam, and with the deviation of the extraordinary wave by 90{sup 0}. Calcite prisms with the deviation angles for the extraordinary beam {approx}19{sup 0} and 90{sup 0} are tested experimentally. (control of laser radiation parameters)

  20. 1. GENERAL VIEW, TOWPATH BERM (CENTER) AND CANAL PRISM (LEFT) ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. GENERAL VIEW, TOWPATH BERM (CENTER) AND CANAL PRISM (LEFT) SOUTH OF THE SPILLWAY; VIEW TO SOUTH. - Blackstone Canal Millbury Segment, Beginning northwest of State Route 146 & McCracken Road, running along west side of Route 146, Millbury, Worcester County, MA

  1. Prism adaptation for spatial neglect after stroke: translational practice gaps

    PubMed Central

    Barrett, A. M.; Goedert, Kelly M.; Basso, Julia C.

    2012-01-01

    Spatial neglect increases hospital morbidity and costs in around 50% of the 795,000 people per year in the USA who survive stroke, and an urgent need exists to reduce the care burden of this condition. However, effective acute treatment for neglect has been elusive. In this article, we review 48 studies of a treatment of intense neuroscience interest: prism adaptation training. Due to its effects on spatial motor ‘aiming’, prism adaptation training may act to reduce neglect-related disability. However, research failed, first, to suggest methods to identify the 50–75% of patients who respond to treatment; second, to measure short-term and long-term outcomes in both mechanism-specific and functionally valid ways; third, to confirm treatment utility during the critical first 8 weeks poststroke; and last, to base treatment protocols on systematic dose–response data. Thus, considerable investment in prism adaptation research has not yet touched the fundamentals needed for clinical implementation. We suggest improved standards and better spatial motor models for further research, so as to clarify when, how and for whom prism adaptation should be applied. PMID:22926312

  2. Acute Chagas Disease: New Global Challenges for an Old Neglected Disease

    PubMed Central

    Andrade, Daniela V.; Gollob, Kenneth J.; Dutra, Walderez O.

    2014-01-01

    Chagas disease is caused by infection with the protozoan Trypanosoma cruzi, and although over 100 years have passed since the discovery of Chagas disease, it still presents an increasing problem for global public health. A plethora of information concerning the chronic phase of human Chagas disease, particularly the severe cardiac form, is available in the literature. However, information concerning events during the acute phase of the disease is scarce. In this review, we will discuss (1) the current status of acute Chagas disease cases globally, (2) the immunological findings related to the acute phase and their possible influence in disease outcome, and (3) reactivation of Chagas disease in immunocompromised individuals, a key point for transplantation and HIV infection management. PMID:25077613

  3. Identifying spatial data availability and spatial data needs for Chagas disease mitigation in South America.

    PubMed

    Morris, Emily; Bone, Christopher

    2016-05-01

    The objective of this paper on Chagas disease is to determine the availability and spatial resolution of existing data that can be used to address Chagas disease transmission risk in South America. A literature review was conducted to determine prominent variables that models utilize to assist with efforts to mitigate Chagas disease. Next, a Web search was performed to collect publicly available spatial data pertaining to these variables for the countries in South America. The data were classified based on type and spatial extent, which were then used to create maps of data availability of variables related to Chagas disease transmission. Governments can use this information to better direct their resources to collect data and control the spread of triatomines and Chagas more effectively, and potentially identify more cost-effective strategies for eliminating triatomine vectors.

  4. Prism adaptation contrasts perceptual habituation for repetitive somatosensory stimuli.

    PubMed

    Torta, D M; Tatu, M K; Cotroneo, D; Alamia, A; Folegatti, A; Trojan, J

    2016-03-01

    Prism adaptation (PA) is a non-invasive procedure that requires performing a visuo-motor pointing task while wearing prism goggles inducing a visual displacement of the pointed target. This procedure involves a reorganization of sensorimotor coordination, and induces long-lasting effects on numerous higher-order cognitive functions in healthy volunteers and neglect patients. Prismatic displacement (PD) of the visual field can be induced when prisms are worn but no sensorimotor task is required. In this case, it is unlikely that any subsequent reorganization takes place. The effects of PD are short-lived in the sense that they last as long as prisms are worn. In this study we aimed, to the best of our knowledge for the first time, at investigating whether PA and PD induce changes in the perception of intensity of nociceptive and non- nociceptive somatosensory stimuli. We induced, in healthy volunteers, PD (experiment 1), or PA (experiment 2) and asked participants to rate the intensity of the stimuli applied to the hand undergoing the visuo-proprioceptive conflict (experiment 1) or adaptation (experiment 2). Our results indicate that: 1) the visuo-proprioceptive conflict induced by PD does not reduce the perceived intensity of the stimuli, 2) PA prevents perceptual habituation for both nociceptive and non-nociceptive somatosensory stimuli. Moreover, to investigate the possible underlying mechanisms of the effects of PA we conducted a third experiment in which stimuli were applied both at the adapted and the non-adapted hand. In line with the results of experiment 2, we found that perceptual habituation was prevented for stimuli applied onto the adapted hand. Moreover, we observed the same finding for stimuli applied onto the non-adapted hand. This result suggests that the detention of habituation is not merely driven by changes in spatial attention allocation. Taken together, these data indicate that prisms can affect the perceived intensity of somatosensory stimuli

  5. Superconducting magnetic Wollaston prism for neutron spin encoding

    SciTech Connect

    Li, F. Parnell, S. R.; Wang, T.; Baxter, D. V.; Hamilton, W. A.; Maranville, B. B.; Semerad, R.; Cremer, J. T.; Pynn, R.

    2014-05-15

    A magnetic Wollaston prism can spatially split a polarized neutron beam into two beams with different neutron spin states, in a manner analogous to an optical Wollaston prism. Such a Wollaston prism can be used to encode the trajectory of neutrons into the Larmor phase associated with their spin degree of freedom. This encoding can be used for neutron phase-contrast radiography and in spin echo scattering angle measurement (SESAME). In this paper, we show that magnetic Wollaston prisms with highly uniform magnetic fields and low Larmor phase aberration can be constructed to preserve neutron polarization using high temperature superconducting (HTS) materials. The Meissner effect of HTS films is used to confine magnetic fields produced electromagnetically by current-carrying HTS tape wound on suitably shaped soft iron pole pieces. The device is cooled to ∼30 K by a closed cycle refrigerator, eliminating the need to replenish liquid cryogens and greatly simplifying operation and maintenance. A HTS film ensures that the magnetic field transition within the prism is sharp, well-defined, and planar due to the Meissner effect. The spin transport efficiency across the device was measured to be ∼98.5% independent of neutron wavelength and energizing current. The position-dependent Larmor phase of neutron spins was measured at the NIST Center for Neutron Research facility and found to agree well with detailed simulations. The phase varies linearly with horizontal position, as required, and the neutron beam shows little depolarization. Consequently, the device has advantages over existing devices with similar functionality and provides the capability for a large neutron beam (20 mm × 30 mm) and an increase in length scales accessible to SESAME to beyond 10 μm. With further improvements of the external coupling guide field in the prototype device, a larger neutron beam could be employed.

  6. Study of dose calculation on breast brachytherapy using prism TPS

    SciTech Connect

    Fendriani, Yoza; Haryanto, Freddy

    2015-09-30

    PRISM is one of non-commercial Treatment Planning System (TPS) and is developed at the University of Washington. In Indonesia, many cancer hospitals use expensive commercial TPS. This study aims to investigate Prism TPS which been applied to the dose distribution of brachytherapy by taking into account the effect of source position and inhomogeneities. The results will be applicable for clinical Treatment Planning System. Dose calculation has been implemented for water phantom and CT scan images of breast cancer using point source and line source. This study used point source and line source and divided into two cases. On the first case, Ir-192 seed source is located at the center of treatment volume. On the second case, the source position is gradually changed. The dose calculation of every case performed on a homogeneous and inhomogeneous phantom with dimension 20 × 20 × 20 cm{sup 3}. The inhomogeneous phantom has inhomogeneities volume 2 × 2 × 2 cm{sup 3}. The results of dose calculations using PRISM TPS were compared to literature data. From the calculation of PRISM TPS, dose rates show good agreement with Plato TPS and other study as published by Ramdhani. No deviations greater than ±4% for all case. Dose calculation in inhomogeneous and homogenous cases show similar result. This results indicate that Prism TPS is good in dose calculation of brachytherapy but not sensitive for inhomogeneities. Thus, the dose calculation parameters developed in this study were found to be applicable for clinical treatment planning of brachytherapy.

  7. Experimental static aerodynamics of a regular hexagonal prism in a low density hypervelocity flow

    NASA Technical Reports Server (NTRS)

    Guy, R. W.; Mueller, J. N.; Lee, L. P.

    1972-01-01

    A regular hexagonal prism, having a fineness ratio of 1.67, has been tested in a wind tunnel to determine its static aerodynamic characteristics in a low-density hypervelocity flow. The prism tested was a 1/4-scale model of the graphite heat shield which houses the radioactive fuel for the Viking spacecraft auxiliary power supply. The basic hexagonal prism was also modified to simulate a prism on which ablation of one of the six side flats had occurred. This modified hexagonal prism was tested to determine the effects on the aerodynamic characteristics of a shape change caused by ablation during a possible side-on stable reentry.

  8. IL18 Gene Variants Influence the Susceptibility to Chagas Disease.

    PubMed

    Leon Rodriguez, Daniel A; Carmona, F David; Echeverría, Luis Eduardo; González, Clara Isabel; Martin, Javier

    2016-03-01

    Chagas disease is a parasitic disorder caused by the infection with the flagellated protozoan Trypanosoma cruzi. According to the World Health Organization, more than six million people are currently infected in endemic regions. Genetic factors have been proposed to influence predisposition to infection and development of severe clinical phenotypes like chronic Chagas cardiomyopathy (CCC). Interleukin 18 (IL18) encodes a proinflammatory cytokine that has been proposed to be involved in controlling T. cruzi infection. In this study, we analyzed the possible role of six IL18 gene variants (rs5744258, rs360722, rs2043055, rs187238, rs1946518 and rs360719), which cover most of the variation within the locus, in the susceptibility to infection by T. cruzi and/or CCC. In total, 1,171 individuals from a Colombian region endemic for Chagas disease, classified as seronegative (n = 595), seropositive asymptomatic (n = 175) and CCC (n = 401), were genotyped using TaqMan probes. Significant associations with T. cruzi infection were observed when comparing seronegative and seropositive individuals for rs187238 (P = 2.18E-03, OR = 0.77), rs360719 (P = 1.49E-03, OR = 0.76), rs2043055 (P = 2.52E-03, OR = 1.29), and rs1946518 (P = 0.0162, OR = 1.22). However, dependence analyses suggested that the association was mainly driven by the polymorphism rs360719. This variant is located within the promoter region of the IL18 gene, and it has been described that it creates a binding site for the transcription factor OCT-1 affecting IL-18 expression levels. In addition, no evidence of association was observed between any of the analyzed IL18 gene polymorphisms and the development of CCC. In summary, our data suggest that genetic variation within the promoter region of IL18 is directly involved in the susceptibility to infection by T. cruzi, which provides novel insight into disease pathophysiology and adds new perspectives to achieve a more effective disease control.

  9. Retracing Micro-Epidemics of Chagas Disease Using Epicenter Regression

    PubMed Central

    Levy, Michael Z.; Small, Dylan S.; Vilhena, Daril A.; Bowman, Natalie M.; Kawai, Vivian; Cornejo del Carpio, Juan G.; Cordova-Benzaquen, Eleazar; Gilman, Robert H.; Bern, Caryn; Plotkin, Joshua B.

    2011-01-01

    Vector-borne transmission of Chagas disease has become an urban problem in the city of Arequipa, Peru, yet the debilitating symptoms that can occur in the chronic stage of the disease are rarely seen in hospitals in the city. The lack of obvious clinical disease in Arequipa has led to speculation that the local strain of the etiologic agent, Trypanosoma cruzi, has low chronic pathogenicity. The long asymptomatic period of Chagas disease leads us to an alternative hypothesis for the absence of clinical cases in Arequipa: transmission in the city may be so recent that most infected individuals have yet to progress to late stage disease. Here we describe a new method, epicenter regression, that allows us to infer the spatial and temporal history of disease transmission from a snapshot of a population's infection status. We show that in a community of Arequipa, transmission of T. cruzi by the insect vector Triatoma infestans occurred as a series of focal micro-epidemics, the oldest of which began only around 20 years ago. These micro-epidemics infected nearly 5% of the community before transmission of the parasite was disrupted through insecticide application in 2004. Most extant human infections in our study community arose over a brief period of time immediately prior to vector control. According to our findings, the symptoms of chronic Chagas disease are expected to be absent, even if the strain is pathogenic in the chronic phase of disease, given the long asymptomatic period of the disease and short history of intense transmission. Traducción al español disponible en Alternative Language Text S1/A Spanish translation of this article is available in Alternative Language Text S1 PMID:21935346

  10. Retracing micro-epidemics of Chagas disease using epicenter regression.

    PubMed

    Levy, Michael Z; Small, Dylan S; Vilhena, Daril A; Bowman, Natalie M; Kawai, Vivian; Cornejo del Carpio, Juan G; Cordova-Benzaquen, Eleazar; Gilman, Robert H; Bern, Caryn; Plotkin, Joshua B

    2011-09-01

    Vector-borne transmission of Chagas disease has become an urban problem in the city of Arequipa, Peru, yet the debilitating symptoms that can occur in the chronic stage of the disease are rarely seen in hospitals in the city. The lack of obvious clinical disease in Arequipa has led to speculation that the local strain of the etiologic agent, Trypanosoma cruzi, has low chronic pathogenicity. The long asymptomatic period of Chagas disease leads us to an alternative hypothesis for the absence of clinical cases in Arequipa: transmission in the city may be so recent that most infected individuals have yet to progress to late stage disease. Here we describe a new method, epicenter regression, that allows us to infer the spatial and temporal history of disease transmission from a snapshot of a population's infection status. We show that in a community of Arequipa, transmission of T. cruzi by the insect vector Triatoma infestans occurred as a series of focal micro-epidemics, the oldest of which began only around 20 years ago. These micro-epidemics infected nearly 5% of the community before transmission of the parasite was disrupted through insecticide application in 2004. Most extant human infections in our study community arose over a brief period of time immediately prior to vector control. According to our findings, the symptoms of chronic Chagas disease are expected to be absent, even if the strain is pathogenic in the chronic phase of disease, given the long asymptomatic period of the disease and short history of intense transmission. Traducción al español disponible en Alternative Language Text S1/A Spanish translation of this article is available in Alternative Language Text S1.

  11. Resveratrol Reverses Functional Chagas Heart Disease in Mice

    PubMed Central

    Mata-Santos, Hilton; Vicentino, Amanda R. R.; Feijó, Daniel F.; Meyer-Fernandes, José R.; Paula-Neto, Heitor A.; Medei, Emiliano; Bozza, Marcelo T.; Lannes-Vieira, Joseli; Paiva, Claudia N.

    2016-01-01

    Chronic chagasic cardiomyopathy (CCC) develops years after acute infection by Trypanosoma cruzi and does not improve after trypanocidal therapy, despite reduction of parasite burden. During disease, the heart undergoes oxidative stress, a potential causative factor for arrhythmias and contractile dysfunction. Here we tested whether antioxidants/ cardioprotective drugs could improve cardiac function in established Chagas heart disease. We chose a model that resembles B1-B2 stage of human CCC, treated mice with resveratrol and performed electrocardiography and echocardiography studies. Resveratrol reduced the prolonged PR and QTc intervals, increased heart rates and reversed sinus arrhythmia, atrial and atrioventricular conduction disorders; restored a normal left ventricular ejection fraction, improved stroke volume and cardiac output. Resveratrol activated the AMPK-pathway and reduced both ROS production and heart parasite burden, without interfering with vascularization or myocarditis intensity. Resveratrol was even capable of improving heart function of infected mice when treatment was started late after infection, while trypanocidal drug benznidazole failed. We attempted to mimic resveratrol’s actions using metformin (AMPK-activator) or tempol (SOD-mimetic). Metformin and tempol mimicked the beneficial effects of resveratrol on heart function and decreased lipid peroxidation, but did not alter parasite burden. These results indicate that AMPK activation and ROS neutralization are key strategies to induce tolerance to Chagas heart disease. Despite all tissue damage observed in established Chagas heart disease, we found that a physiological dysfunction can still be reversed by treatment with resveratrol, metformin and tempol, resulting in improved heart function and representing a starting point to develop innovative therapies in CCC. PMID:27788262

  12. Cuticular hydrocarbons of Chagas disease vectors in Mexico.

    PubMed

    Juarez, M Patricia; Carlson, David A; Salazar Schettino, Paz María; Mijailovsky, Sergio; Rojas, Gloria

    2002-09-01

    Capillary gas-liquid chromatography was used to analyse the cuticular hydrocarbons of three triatomine species, Triatoma dimidiata, T. barberi and Dipetalogaster maxima, domestic vectors of Chagas disease in Mexico. Mixtures of saturated hydrocarbons of straight and methyl-branched chains were characteristic of the three species, but quantitatively different. Major methylbranched components mostly corresponded to different saturated isomers of monomethyl, dimethyl and trimethyl branched hydrocarbons ranging from 29 to 39 carbon backbones. Sex-dependent, quantitative differences in certain hydrocarbons were apparent in T. dimidiata.

  13. Diagnosis of Chagas' cardiomyopathy. Non-invasive techniques.

    PubMed Central

    Puigbó, J. J.; Valecillos, R.; Hirschhaut, E.; Giordano, H.; Boccalandro, I.; Suárez, C.; Aparicio, J. M.

    1977-01-01

    The natural history of Chagas' disease and its manifestations when the heart is involved are detailed clinically and pathologically. Three phases are recognized: the acute phase, lasting from 1-3 months, the latent phase, which may last from 10-20 years, and the chronic phase, which has the most serious manifestations. This phase is subdivided into three clinical stages. An analysis of the varied cardiac manifestations on 235 patients is included. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 PMID:412174

  14. [Chagas disease. American trypanosomiasis. Recommendation for non-endemic zones].

    PubMed

    2010-04-01

    The following recommendations were made at the end of the consensus workshop organized by the Société de Pathologie Exotique (Exotic Pathology Society) (Paris, 26 June 2009). They apply to people of Latin American origin (immigrants, children born in France to a Latin-American mother, French people originating in Guyana) and expatriates and travellers who have stayed in areas where Chagas disease is endemic. These recommendations concern screening for people who are infected but asymptomatic, diagnosis of acute forms, diagnosis of chronic forms with clinical manifestations and therapeutic procedure.

  15. When a misperception favors a tragedy: Carlos Chagas and the Nobel Prize of 1921.

    PubMed

    Bestetti, Reinaldo B; Couto, Lucélio B; Cardinalli-Neto, Augusto

    2013-11-20

    Carlos Chagas, the discoverer of Chagas' disease was nominated to the Nobel Prize in 1921, but none did win the prize in that year. As a leader of a young scientist team, he discovered all aspects of the new disease from 1909 to 1920. It is still obscure why he did not win the Nobel Prize in 1921. Chagas was discarded by Gunnar Hedrèn on April 16, 1921. Hedrèn should have made a written report about the details of his evaluation to the Nobel Committee. However, such a document has not been found in the Nobel Committee Archives. No evidence of detractions made by Brazilian scientists on Chagas was found. Since Chagas nomination was consistent with the Nobel Committee requirements, as seen in the presentation letter by until now unknown Cypriano de Freitas, it become clear that Chagas did not win the Nobel Prize exclusively because the Nobel Committee did not perceive the importance of his discovery. Thus, it would be fair a posthumous Nobel Prize of 1921 to Carlos Chagas. A diploma of the Nobel Prize, as precedent with Dogmack in 1947, would recognize the merit of the scientist who made the most complete medical discovery of all times.

  16. Risks of endemicity, morbidity and perspectives regarding the control of Chagas disease in the Amazon Region.

    PubMed

    Coura, José Rodrigues; Junqueira, Angela Cv

    2012-03-01

    Chagas disease, in the Amazon Region as elsewhere, can be considered an enzootic disease of wild animals or an anthropozoonosis, an accidental disease of humans that is acquired when humans penetrate a wild ecosystem or when wild triatomines invade human dwellings attracted by light or searching for human blood. The risk of endemic Chagas disease in the Amazon Region is associated with the following phenomena: (i) extensive deforestation associated with the displacement of wild mammals, which are the normal sources of blood for triatomines, (ii) adaptation of wild triatomines to human dwellings due to the need for a new source of blood for feeding and (iii) uncontrolled migration of human populations and domestic animals that are already infected with Trypanosoma cruzi from areas endemic for Chagas disease to the Amazon Region. Several outbreaks of severe acute cases of Chagas disease, as well as chronic cases, have been described in the Amazon Region. Control measures targeted to avoiding endemic Chagas disease in the Amazon Region should be the following: improving health education in communities, training public health officials and communities for vector and Chagas disease surveillance and training local physicians to recognise and treat acute and chronic cases of Chagas diseases as soon as possible.

  17. Chagas Disease Awareness among Latin American Immigrants Living in Los Angeles, California

    PubMed Central

    Sanchez, Daniel R.; Traina, Mahmoud I.; Hernandez, Salvador; Smer, Aiman M.; Khamag, Haneen; Meymandi, Sheba K.

    2014-01-01

    Approximately 300,000 persons have Chagas disease in the United States, although almost all persons acquired the disease in Latin America. We examined awareness of Chagas disease among Latin American immigrants living in Los Angeles, California. We surveyed 2,677 persons (age range = 18–60 years) in Los Angeles who resided in Latin America for at least six months. A total of 62% of the participants recalled seeing triatomines in Latin America, and 27% of the participants reported triatomine bites at least once per year while living abroad. A total of 86% of the participants had never heard of Chagas disease. Of persons who had heard of Chagas disease, 81% believed that it was not serious. More than 95% of those who had heard of Chagas disease would want to be tested and treated. Most Latin American immigrants living in Los Angeles recalled exposure to vectors of Chagas disease. However, they have little knowledge of this disease. Increasing awareness of Chagas disease is needed in this high-risk population. PMID:25200261

  18. Planar prism spectrometer based on adiabatically connected waveguiding slabs

    NASA Astrophysics Data System (ADS)

    Civitci, F.; Hammer, M.; Hoekstra, H. J. W. M.

    2016-04-01

    The device principle of a prism-based on-chip spectrometer for TE polarization is introduced. The spectrometer exploits the modal dispersion in planar waveguides in a layout with slab regions having two different thicknesses of the guiding layer. The set-up uses parabolic mirrors, for the collimation of light of the input waveguide and focusing of the light to the receiver waveguides, which relies on total internal reflection at the interface between two such regions. These regions are connected adiabatically to prevent unwanted mode conversion and loss at the edges of the prism. The structure can be fabricated with two wet etching steps. The paper presents basic theory and a general approach for device optimization. The latter is illustrated with a numerical example assuming SiON technology.

  19. Stereovision Imaging in Smart Mobile Phone Using Add on Prisms

    NASA Astrophysics Data System (ADS)

    Bar-Magen Numhauser, Jonathan; Zalevsky, Zeev

    2014-03-01

    In this work we present the use of a prism-based add on component installed on top of a smart phone to achieve stereovision capabilities using iPhone mobile operating system. Through these components and the combination of the appropriate application programming interface and mathematical algorithms the obtained results will permit the analysis of possible enhancements for new uses to such system, in a variety of areas including medicine and communications.

  20. Prism-coupled light emission from tunnel junctions

    NASA Technical Reports Server (NTRS)

    Ushioda, S.; Rutledge, J. E.; Pierce, R. M.

    1985-01-01

    Completely p-polarized light emission has been observed from smooth Al-AlO(x)-Au tunnel junctions placed on a prism coupler. The angle and polarization dependence demonstrate unambiguously that the emitted light is radiated by the fast-mode surface plasmon polariton. The emission spectra suggest that the dominant process for the excitation of the fast mode is through conversion of the slow mode to the fast mode mediated by residual roughness on the junction surface.

  1. Squalene Synthase As a Target for Chagas Disease Therapeutics

    PubMed Central

    Chan, Hsiu-Chien; Li, Jikun; Zheng, Yingying; Huang, Chun-Hsiang; Ren, Feifei; Chen, Chun-Chi; Zhu, Zhen; Galizzi, Melina; Li, Zhu-Hong; Rodrigues-Poveda, Carlos A.; Gonzalez-Pacanowska, Dolores; Veiga-Santos, Phercyles; de Carvalho, Tecia Maria Ulisses; de Souza, Wanderley; Urbina, Julio A.; Wang, Andrew H.-J.; Docampo, Roberto; Li, Kai; Liu, Yi-Liang; Oldfield, Eric; Guo, Rey-Ting

    2014-01-01

    Trypanosomatid parasites are the causative agents of many neglected tropical diseases and there is currently considerable interest in targeting endogenous sterol biosynthesis in these organisms as a route to the development of novel anti-infective drugs. Here, we report the first x-ray crystallographic structures of the enzyme squalene synthase (SQS) from a trypanosomatid parasite, Trypanosoma cruzi, the causative agent of Chagas disease. We obtained five structures of T. cruzi SQS and eight structures of human SQS with four classes of inhibitors: the substrate-analog S-thiolo-farnesyl diphosphate, the quinuclidines E5700 and ER119884, several lipophilic bisphosphonates, and the thiocyanate WC-9, with the structures of the two very potent quinuclidines suggesting strategies for selective inhibitor development. We also show that the lipophilic bisphosphonates have low nM activity against T. cruzi and inhibit endogenous sterol biosynthesis and that E5700 acts synergistically with the azole drug, posaconazole. The determination of the structures of trypanosomatid and human SQS enzymes with a diverse set of inhibitors active in cells provides insights into SQS inhibition, of interest in the context of the development of drugs against Chagas disease. PMID:24789335

  2. Squalene synthase as a target for Chagas disease therapeutics.

    PubMed

    Shang, Na; Li, Qian; Ko, Tzu-Ping; Chan, Hsiu-Chien; Li, Jikun; Zheng, Yingying; Huang, Chun-Hsiang; Ren, Feifei; Chen, Chun-Chi; Zhu, Zhen; Galizzi, Melina; Li, Zhu-Hong; Rodrigues-Poveda, Carlos A; Gonzalez-Pacanowska, Dolores; Veiga-Santos, Phercyles; de Carvalho, Tecia Maria Ulisses; de Souza, Wanderley; Urbina, Julio A; Wang, Andrew H-J; Docampo, Roberto; Li, Kai; Liu, Yi-Liang; Oldfield, Eric; Guo, Rey-Ting

    2014-05-01

    Trypanosomatid parasites are the causative agents of many neglected tropical diseases and there is currently considerable interest in targeting endogenous sterol biosynthesis in these organisms as a route to the development of novel anti-infective drugs. Here, we report the first x-ray crystallographic structures of the enzyme squalene synthase (SQS) from a trypanosomatid parasite, Trypanosoma cruzi, the causative agent of Chagas disease. We obtained five structures of T. cruzi SQS and eight structures of human SQS with four classes of inhibitors: the substrate-analog S-thiolo-farnesyl diphosphate, the quinuclidines E5700 and ER119884, several lipophilic bisphosphonates, and the thiocyanate WC-9, with the structures of the two very potent quinuclidines suggesting strategies for selective inhibitor development. We also show that the lipophilic bisphosphonates have low nM activity against T. cruzi and inhibit endogenous sterol biosynthesis and that E5700 acts synergistically with the azole drug, posaconazole. The determination of the structures of trypanosomatid and human SQS enzymes with a diverse set of inhibitors active in cells provides insights into SQS inhibition, of interest in the context of the development of drugs against Chagas disease. PMID:24789335

  3. [Composition and biological activity of triterpenes and steroids from Inonotus obliquus (chaga)].

    PubMed

    Nikitina, S A; Khabibrakhmanova, V R; Sysoeva, M A

    2016-05-01

    Data on the chemical composition of triterpenic and steroid compounds, isolated from the chaga mushroom grown in natural environment or in a synthetic culture have been summarized. Special attention has been paid to the biological activity of chaga mushroom extracts and these particular compounds against various cancer cell lines in vitro and in vivo. This analysis has demonstrated some common features in inhibition of growth of various cell lines by chaga mushroom components. In this context, the most active are triterpene compounds containing OH group at C-22 and a side chain unsaturated bond. PMID:27562990

  4. Spatial compression impairs prism adaptation in healthy individuals.

    PubMed

    Scriven, Rachel J; Newport, Roger

    2013-01-01

    Neglect patients typically present with gross inattention to one side of space following damage to the contralateral hemisphere. While prism-adaptation (PA) is effective in ameliorating some neglect behaviors, the mechanisms involved and their relationship to neglect remain unclear. Recent studies have shown that conscious strategic control (SC) processes in PA may be impaired in neglect patients, who are also reported to show extraordinarily long aftereffects compared to healthy participants. Determining the underlying cause of these effects may be the key to understanding therapeutic benefits. Alternative accounts suggest that reduced SC might result from a failure to detect prism-induced reaching errors properly either because (a) the size of the error is underestimated in compressed visual space or (b) pathologically increased error-detection thresholds reduce the requirement for error correction. The purpose of this study was to model these two alternatives in healthy participants and to examine whether SC and subsequent aftereffects were abnormal compared to standard PA. Each participant completed three PA procedures within a MIRAGE mediated reality environment with direction errors recorded before, during and after adaptation. During PA, visual feedback of the reach could be compressed, perturbed by noise, or represented veridically. Compressed visual space significantly reduced SC and aftereffects compared to control and noise conditions. These results support recent observations in neglect patients, suggesting that a distortion of spatial representation may successfully model neglect and explain neglect performance while adapting to prisms. PMID:23675332

  5. Controllable Sonar Lenses and Prisms Based on ERFs

    NASA Technical Reports Server (NTRS)

    Bar-Cohen, Yoseph; Sherrit, Stewart; Chang, Zensheu; Bao, Xiaoqi; Paustian, Iris; Lopes, Joseph; Folds, Donald

    2004-01-01

    Sonar-beam-steering devices of the proposed type would contain no moving parts and would be considerably smaller and less power-hungry, relative to conventional multiple-beam sonar arrays. The proposed devices are under consideration for installation on future small autonomous underwater vehicles because the sizes and power demands of conventional multiple-beam arrays are excessive, and motors used in single-beam mechanically scanned systems are also not reliable. The proposed devices would include a variety of electrically controllable acoustic prisms, lenses, and prism/lens combinations both simple and compound. These devices would contain electrorheological fluids (ERFs) between electrodes. An ERF typically consists of dielectric particles floating in a dielectric fluid. When an electric field is applied to the fluid, the particles become grouped into fibrils aligned in rows, with a consequent increase in the viscosity of the fluid and a corresponding increase in the speed of sound in the fluid. The change in the speed of sound increases with an increase in the applied electric field. By thus varying the speed of sound, one varies the acoustic index of refraction, analogously to varying the index of refraction of an optical lens or prism. In the proposed acoustic devices, this effect would be exploited to control the angles of refraction of acoustic beams, thereby steering the beams and, in the case of lenses, controlling focal lengths.

  6. Effect of prism adaptation on thermoregulatory control in humans.

    PubMed

    Calzolari, Elena; Gallace, Alberto; Moseley, G Lorimer; Vallar, Giuseppe

    2016-01-01

    The physiological regulation of skin temperature can be modulated not only by autonomic brain regions, but also by a network of higher-level cortical areas involved in the maintenance of a coherent representation of the body. In this study we assessed in healthy participants if the sensorimotor changes taking place during motor adaptation to the lateral displacement of the visual scene induced by wearing prismatic lenses (prism adaptation, PA), and the aftereffects, after prisms' removal, on the ability to process spatial coordinates, were associated with skin temperature regulation changes. We found a difference in thermoregulatory control as a function of the direction of the prism-induced displacement of the visual scene, and the subsequent sensorimotor adaptation. After PA to rightward displacing lenses, with leftward aftereffects (the same directional procedure efficaciously used for ameliorating left spatial neglect in right-brain-damaged patients) the hands' temperature decreased. Conversely, after adaptation to neutral lenses, and PA to leftward displacing lenses, with rightward aftereffects, the temperature of both hands increased. These results suggest a lateral asymmetry in the effects of PA on skin temperature regulation, and a relationship between body spatial representations and homeostatic control in humans.

  7. Control system design for a double-prism scanner

    NASA Astrophysics Data System (ADS)

    Zhang, Hao; Yuan, Yan; Zhao, Yanyan; Su, Lijuan

    2013-12-01

    A control system designed for a Double-Prism scanner is discussed in this paper. This control system is required to regulate the speed of prisms accurately and change the scan pattern as quickly as possible. Therefore, we designed a digital double closed-loop control system which consists of an inner loop and an outer loop to achieve that function. In this double closed-loop control system, the inner loop uses linear Proportional-Integral (PI) controller for the current control and the outer loop uses saturated Proportional-Integral controller for the speed control. To verify the feasibility and rationality of this control method, simulation based on MATLAB was performed. And the simulation results indicate that the step response of prism speed is stable and there is no steady state error. After building the digital control system, many experiments were performed to obtain key characteristics. The experiment results show that the speed regulation time is about 0.4s when the reference speed is 1rps. The accuracy of speed regulation reaches 10-4 level, and the fluctuation ratio of speed regulation reaches 10-2 level over its operation range(0rps-3rps).

  8. Stabilization of a self-referenced, prism-based, Cr:forsterite laser frequency comb using an intracavity prism

    SciTech Connect

    Tillman, Karl A.; Thapa, Rajesh; Knabe, Kevin; Wu Shun; Lim, Jinkang; Washburn, Brian R.; Corwin, Kristan L.

    2009-12-20

    The frequency comb from a prism-based Cr:forsterite laser has been frequency stabilized using intracavity prism insertion and pump power modulation. Absolute frequency measurements of a CW fiber laser stabilized to the P(13) transition of acetylene demonstrate a fractional instability of {approx}2x10{sup -11} at a 1 s gate time, limited by a commercial Global Positioning System (GPS)-disciplined rubidium oscillator. Additionally, absolute frequency measurements made simultaneously using a second frequency comb indicate relative instabilities of 3x10{sup -12} for both combs for a 1 s gate time. Estimations of the carrier-envelope offset frequency linewidth based on relative intensity noise and the response dynamics of the carrier-envelope offset to pump power changes confirm the observed linewidths.

  9. Forest Biomass Mapping from Prism Triplet, Palsar and Landsat Data

    NASA Astrophysics Data System (ADS)

    Ranson, J.; Sun, G.; Ni, W.

    2014-12-01

    The loss of sensitivity at higher biomass levels is a common problem in biomass mapping using optical multi-spectral data or radar backscattering data due to the lack of information on canopy vertical structure. Studies have shown that adding implicit information of forest vertical structure improves the performance of forest biomass mapping from optical reflectance and radar backscattering data. LiDAR, InSAR and stereo imager are the data sources for obtaining forest structural information. The potential of providing information on forest vertical structure by stereoscopic imagery data has drawn attention recently due to the availability of high-resolution digital stereo imaging from space and the advances of digital stereo image processing software. The Panchromatic Remote-sensing Instrument for Stereo Mapping (PRISM) onboard the Advanced Land Observation Satellite (ALOS) has acquired multiple global coverage from June 2006 to April 2011 providing a good data source for regional/global forest studies. In this study, five PRISM triplets acquired on June 14, 2008, August 19 and September 5, 2009; PALSAR dual-pol images acquired on July 12, 2008 and August 30, 2009; and LANDSAT 5 TM images acquired on September 5, 2009 and the field plot data collected in 2009 and 2010 were used to map forest biomass at 50m pixel in an area of about 4000 km2in Maine, USA ( 45.2 deg N 68.6 deg W). PRISM triplets were used to generate point cloud data at 2m pixel first and then the average height of points above NED (National Elevation Dataset) within a 50m by 50m pixel was calculated. Five images were mosaicked and used as canopy height information in the biomass estimation along with the PALSAR HH, HV radar backscattering and optical reflectance vegetation indices from L-5 TM data. A small portion of this region was covered by the Land Vegetation and Ice Sensor (LVIS) in 2009. The biomass maps from the LVIS data was used to evaluate the results from combined use of PRISM, PALSAR and

  10. Short report: Increasing access to treatment for Chagas disease: the case of Morelos, Mexico.

    PubMed

    Manne-Goehler, Jennifer; Ramsey, Janine M; Salgado, Marco Ocampo; Wirtz, Veronika J; Reich, Michael R

    2014-12-01

    Chagas disease is a neglected vector-borne disease with an estimated prevalence of 1.1 million cases in Mexico. Recent research showed that access to treatment of Chagas disease is limited in Mexico, with < 0.5% of infected cases treated. This brief report used quantitative data from the Morelos Program on Chagas disease and qualitative analysis of key informant interviews to examine strategies to increase treatment access for infected patients in Morelos, Mexico. From 2007 to 2011, 263 (9.2%) of the registered cases of Chagas disease in Mexico occurred in Morelos. Among these, 152 (57.8%) were treated and 97.3% of those treated received benznidazole. The assessment finds that state officials decided to directly purchase benznidazole from the distributor to increase access and improve clinical quality of treatment of patients in their state. They also faced significant barriers, especially in regulation and health system organization, which limited efforts to make high quality treatment available.

  11. Gene-deleted live-attenuated Trypanosoma cruzi parasites as vaccines to protect against Chagas disease.

    PubMed

    Sánchez-Valdéz, Fernando J; Pérez Brandán, Cecilia; Ferreira, Arturo; Basombrío, Miguel Ángel

    2015-05-01

    Chagas disease is a neglected tropical disease caused by the protozoan parasite Trypanosoma cruzi. This illness is now becoming global, mainly due to congenital transmission, and so far, there are no prophylactic or therapeutic vaccines available to either prevent or treat Chagas disease. Therefore, different approaches aimed at identifying new protective immunogens are urgently needed. Live vaccines are likely to be more efficient in inducing protection, but safety issues linked with their use have been raised. The development of improved protozoan genetic manipulation tools and genomic and biological information has helped to increase the safety of live vaccines. These advances have generated a renewed interest in the use of genetically attenuated parasites as vaccines against Chagas disease. This review discusses the protective capacity of genetically attenuated parasite vaccines and the challenges and perspectives for the development of an effective whole-parasite Chagas disease vaccine.

  12. On palms, bugs, and Chagas disease in the Americas.

    PubMed

    Abad-Franch, Fernando; Lima, Marli M; Sarquis, Otília; Gurgel-Gonçalves, Rodrigo; Sánchez-Martín, María; Calzada, José; Saldaña, Azael; Monteiro, Fernando A; Palomeque, Francisco S; Santos, Walter S; Angulo, Victor M; Esteban, Lyda; Dias, Fernando B S; Diotaiuti, Liléia; Bar, María Esther; Gottdenker, Nicole L

    2015-11-01

    Palms are ubiquitous across Neotropical landscapes, from pristine forests or savannahs to large cities. Although palms provide useful ecosystem services, they also offer suitable habitat for triatomines and for Trypanosoma cruzi mammalian hosts. Wild triatomines often invade houses by flying from nearby palms, potentially leading to new cases of human Chagas disease. Understanding and predicting triatomine-palm associations and palm infestation probabilities is important for enhancing Chagas disease prevention in areas where palm-associated vectors transmit T. cruzi. We present a comprehensive overview of palm infestation by triatomines in the Americas, combining a thorough reanalysis of our published and unpublished records with an in-depth review of the literature. We use site-occupancy modeling (SOM) to examine infestation in 3590 palms sampled with non-destructive methods, and standard statistics to describe and compare infestation in 2940 palms sampled by felling-and-dissection. Thirty-eight palm species (18 genera) have been reported to be infested by ∼39 triatomine species (10 genera) from the USA to Argentina. Overall infestation varied from 49.1-55.3% (SOM) to 62.6-66.1% (dissection), with important heterogeneities among sub-regions and particularly among palm species. Large palms with complex crowns (e.g., Attalea butyracea, Acrocomia aculeata) and some medium-crowned palms (e.g., Copernicia, Butia) are often infested; in slender, small-crowned palms (e.g., Euterpe) triatomines associate with vertebrate nests. Palm infestation tends to be higher in rural settings, but urban palms can also be infested. Most Rhodnius species are probably true palm specialists, whereas Psammolestes, Eratyrus, Cavernicola, Panstrongylus, Triatoma, Alberprosenia, and some Bolboderini seem to use palms opportunistically. Palms provide extensive habitat for enzootic T. cruzi cycles and a critical link between wild cycles and transmission to humans. Unless effective means to

  13. IL18 Gene Variants Influence the Susceptibility to Chagas Disease.

    PubMed

    Leon Rodriguez, Daniel A; Carmona, F David; Echeverría, Luis Eduardo; González, Clara Isabel; Martin, Javier

    2016-03-01

    Chagas disease is a parasitic disorder caused by the infection with the flagellated protozoan Trypanosoma cruzi. According to the World Health Organization, more than six million people are currently infected in endemic regions. Genetic factors have been proposed to influence predisposition to infection and development of severe clinical phenotypes like chronic Chagas cardiomyopathy (CCC). Interleukin 18 (IL18) encodes a proinflammatory cytokine that has been proposed to be involved in controlling T. cruzi infection. In this study, we analyzed the possible role of six IL18 gene variants (rs5744258, rs360722, rs2043055, rs187238, rs1946518 and rs360719), which cover most of the variation within the locus, in the susceptibility to infection by T. cruzi and/or CCC. In total, 1,171 individuals from a Colombian region endemic for Chagas disease, classified as seronegative (n = 595), seropositive asymptomatic (n = 175) and CCC (n = 401), were genotyped using TaqMan probes. Significant associations with T. cruzi infection were observed when comparing seronegative and seropositive individuals for rs187238 (P = 2.18E-03, OR = 0.77), rs360719 (P = 1.49E-03, OR = 0.76), rs2043055 (P = 2.52E-03, OR = 1.29), and rs1946518 (P = 0.0162, OR = 1.22). However, dependence analyses suggested that the association was mainly driven by the polymorphism rs360719. This variant is located within the promoter region of the IL18 gene, and it has been described that it creates a binding site for the transcription factor OCT-1 affecting IL-18 expression levels. In addition, no evidence of association was observed between any of the analyzed IL18 gene polymorphisms and the development of CCC. In summary, our data suggest that genetic variation within the promoter region of IL18 is directly involved in the susceptibility to infection by T. cruzi, which provides novel insight into disease pathophysiology and adds new perspectives to achieve a more effective disease control. PMID:27027876

  14. On palms, bugs, and Chagas disease in the Americas.

    PubMed

    Abad-Franch, Fernando; Lima, Marli M; Sarquis, Otília; Gurgel-Gonçalves, Rodrigo; Sánchez-Martín, María; Calzada, José; Saldaña, Azael; Monteiro, Fernando A; Palomeque, Francisco S; Santos, Walter S; Angulo, Victor M; Esteban, Lyda; Dias, Fernando B S; Diotaiuti, Liléia; Bar, María Esther; Gottdenker, Nicole L

    2015-11-01

    Palms are ubiquitous across Neotropical landscapes, from pristine forests or savannahs to large cities. Although palms provide useful ecosystem services, they also offer suitable habitat for triatomines and for Trypanosoma cruzi mammalian hosts. Wild triatomines often invade houses by flying from nearby palms, potentially leading to new cases of human Chagas disease. Understanding and predicting triatomine-palm associations and palm infestation probabilities is important for enhancing Chagas disease prevention in areas where palm-associated vectors transmit T. cruzi. We present a comprehensive overview of palm infestation by triatomines in the Americas, combining a thorough reanalysis of our published and unpublished records with an in-depth review of the literature. We use site-occupancy modeling (SOM) to examine infestation in 3590 palms sampled with non-destructive methods, and standard statistics to describe and compare infestation in 2940 palms sampled by felling-and-dissection. Thirty-eight palm species (18 genera) have been reported to be infested by ∼39 triatomine species (10 genera) from the USA to Argentina. Overall infestation varied from 49.1-55.3% (SOM) to 62.6-66.1% (dissection), with important heterogeneities among sub-regions and particularly among palm species. Large palms with complex crowns (e.g., Attalea butyracea, Acrocomia aculeata) and some medium-crowned palms (e.g., Copernicia, Butia) are often infested; in slender, small-crowned palms (e.g., Euterpe) triatomines associate with vertebrate nests. Palm infestation tends to be higher in rural settings, but urban palms can also be infested. Most Rhodnius species are probably true palm specialists, whereas Psammolestes, Eratyrus, Cavernicola, Panstrongylus, Triatoma, Alberprosenia, and some Bolboderini seem to use palms opportunistically. Palms provide extensive habitat for enzootic T. cruzi cycles and a critical link between wild cycles and transmission to humans. Unless effective means to

  15. IL18 Gene Variants Influence the Susceptibility to Chagas Disease

    PubMed Central

    Leon Rodriguez, Daniel A; Carmona, F. David; Echeverría, Luis Eduardo; González, Clara Isabel; Martin, Javier

    2016-01-01

    Chagas disease is a parasitic disorder caused by the infection with the flagellated protozoan Trypanosoma cruzi. According to the World Health Organization, more than six million people are currently infected in endemic regions. Genetic factors have been proposed to influence predisposition to infection and development of severe clinical phenotypes like chronic Chagas cardiomyopathy (CCC). Interleukin 18 (IL18) encodes a proinflammatory cytokine that has been proposed to be involved in controlling T. cruzi infection. In this study, we analyzed the possible role of six IL18 gene variants (rs5744258, rs360722, rs2043055, rs187238, rs1946518 and rs360719), which cover most of the variation within the locus, in the susceptibility to infection by T. cruzi and/or CCC. In total, 1,171 individuals from a Colombian region endemic for Chagas disease, classified as seronegative (n = 595), seropositive asymptomatic (n = 175) and CCC (n = 401), were genotyped using TaqMan probes. Significant associations with T. cruzi infection were observed when comparing seronegative and seropositive individuals for rs187238 (P = 2.18E-03, OR = 0.77), rs360719 (P = 1.49E-03, OR = 0.76), rs2043055 (P = 2.52E-03, OR = 1.29), and rs1946518 (P = 0.0162, OR = 1.22). However, dependence analyses suggested that the association was mainly driven by the polymorphism rs360719. This variant is located within the promoter region of the IL18 gene, and it has been described that it creates a binding site for the transcription factor OCT-1 affecting IL-18 expression levels. In addition, no evidence of association was observed between any of the analyzed IL18 gene polymorphisms and the development of CCC. In summary, our data suggest that genetic variation within the promoter region of IL18 is directly involved in the susceptibility to infection by T. cruzi, which provides novel insight into disease pathophysiology and adds new perspectives to achieve a more effective disease control. PMID:27027876

  16. Serological Diagnosis of Chronic Chagas Disease: Is It Time for a Change?

    PubMed

    Abras, Alba; Gállego, Montserrat; Llovet, Teresa; Tebar, Silvia; Herrero, Mercedes; Berenguer, Pere; Ballart, Cristina; Martí, Carmen; Muñoz, Carmen

    2016-06-01

    Chagas disease has spread to areas that are nonendemic for the disease with human migration. Since no single reference standard test is available, serological diagnosis of chronic Chagas disease requires at least two tests. New-generation techniques have significantly improved the accuracy of Chagas disease diagnosis by the use of a large mixture of recombinant antigens with different detection systems, such as chemiluminescence. The aim of the present study was to assess the overall accuracy of a new-generation kit, the Architect Chagas (cutoff, ≥1 sample relative light units/cutoff value [S/CO]), as a single technique for the diagnosis of chronic Chagas disease. The Architect Chagas showed a sensitivity of 100% (95% confidence interval [CI], 99.5 to 100%) and a specificity of 97.6% (95% CI, 95.2 to 99.9%). Five out of six false-positive serum samples were a consequence of cross-reactivity with Leishmania spp., and all of them achieved results of <5 S/CO. We propose the Architect Chagas as a single technique for screening in blood banks and for routine diagnosis in clinical laboratories. Only gray-zone and positive sera with a result of ≤6 S/CO would need to be confirmed by a second serological assay, thus avoiding false-positive sera and the problem of cross-reactivity with Leishmania species. The application of this proposal would result in important savings in the cost of Chagas disease diagnosis and therefore in the management and control of the disease.

  17. Chagas disease in Texas: recognizing the significance and implications of evidence in the literature.

    PubMed

    Hanford, Elaine Jennifer; Zhan, F Benjamin; Lu, Yongmei; Giordano, Alberto

    2007-07-01

    Chagas disease is endemic and is recognized as a major health problem in many Latin American countries. Despite the parallels between socio-economic and environmental conditions in Texas and much of Latin America, Chagas disease is not a notifiable human disease in Texas. Based on extensive review of related literature, this paper seeks to recognize the evidence that Chagas Disease is endemic to Texas but the epidemiological, parasitological and entomological patterns of Chagas disease in Texas are both different from and parallel to other endemic regions. We find that with a growing immigrant human reservoir, the epidemiological differences may be reduced and result in increasing incidence of the disease. Chagas disease should be recognized as an emerging disease among both immigrant and indigenous populations. Without proper actions, Chagas disease will place increasing burden on the health care system. Current medical treatments consist of chemotherapies that carry the risk of serious side effects; curing the potentially fatal disease remains equivocal. Therefore, as shown in South America, prevention is paramount and can be successfully achieved through intervention and education. We conclude that biogeographical research is needed to (1) distinguish the dynamic evolution of the agent-vector-host system, (2) document locations with greater risk and identify mechanisms responsible for observed changes in risk, and (3) assist in developing a model for Triatomid vector-borne disease in states like Texas where the disease is both endemic and may be carried by a sizeable immigrant population. Tracking of Chagas disease and planning for appropriate health care services would also be aided by including Chagas disease on the list of reportable diseases for humans.

  18. Prism adaptation magnitude has differential influences on perceptual versus manual responses.

    PubMed

    Striemer, Christopher L; Russell, Karyn; Nath, Priya

    2016-10-01

    Previous research has indicated that rightward prism adaptation can reduce symptoms of spatial neglect following right brain damage. In addition, leftward prism adaptation can create "neglect-like" patterns of performance in healthy adults on tasks that measure attention and spatial biases. Although a great deal of research has focused on which behaviors are influenced by prism adaptation, very few studies have focused directly on how the magnitude of visual shift induced by prisms might be related to the observed aftereffects, or the effects of prisms on measures of attentional and spatial biases. In the current study, we examined these questions by having groups of healthy adult participants complete manual line bisection and landmark tasks prior to and following adaptation to either 8.5° (15 diopter; n = 22) or 17° (30 diopter; n = 25) leftward shifting prisms. Our results demonstrated a significantly larger rightward shift in straight-ahead pointing (a measure of prism aftereffect) following adaptation to 17°, compared to 8.5° leftward shifting prisms. In addition, only 17° leftward shifting prisms resulted in a significant rightward shift in line bisection following adaptation. However, there was a significant change in performance on the landmark task pre- versus post-adaptation in both the 8.5° and 17° leftward shifting prism groups. Interestingly, correlation analyses indicated that changes in straight-ahead pointing pre- versus post-adaptation were positively correlated with changes in performance on the manual line bisection task, but not the landmark task. These data suggest that larger magnitudes of prism adaptation seem to have a greater influence on tasks that require a response with the adapted hand (i.e., line bisection), compared to tasks that only require a perceptual judgment (i.e., the landmark task). In addition, these data provide further evidence that the effects of prisms on manual and perceptual responses are not related to one

  19. Prism adaptation magnitude has differential influences on perceptual versus manual responses.

    PubMed

    Striemer, Christopher L; Russell, Karyn; Nath, Priya

    2016-10-01

    Previous research has indicated that rightward prism adaptation can reduce symptoms of spatial neglect following right brain damage. In addition, leftward prism adaptation can create "neglect-like" patterns of performance in healthy adults on tasks that measure attention and spatial biases. Although a great deal of research has focused on which behaviors are influenced by prism adaptation, very few studies have focused directly on how the magnitude of visual shift induced by prisms might be related to the observed aftereffects, or the effects of prisms on measures of attentional and spatial biases. In the current study, we examined these questions by having groups of healthy adult participants complete manual line bisection and landmark tasks prior to and following adaptation to either 8.5° (15 diopter; n = 22) or 17° (30 diopter; n = 25) leftward shifting prisms. Our results demonstrated a significantly larger rightward shift in straight-ahead pointing (a measure of prism aftereffect) following adaptation to 17°, compared to 8.5° leftward shifting prisms. In addition, only 17° leftward shifting prisms resulted in a significant rightward shift in line bisection following adaptation. However, there was a significant change in performance on the landmark task pre- versus post-adaptation in both the 8.5° and 17° leftward shifting prism groups. Interestingly, correlation analyses indicated that changes in straight-ahead pointing pre- versus post-adaptation were positively correlated with changes in performance on the manual line bisection task, but not the landmark task. These data suggest that larger magnitudes of prism adaptation seem to have a greater influence on tasks that require a response with the adapted hand (i.e., line bisection), compared to tasks that only require a perceptual judgment (i.e., the landmark task). In addition, these data provide further evidence that the effects of prisms on manual and perceptual responses are not related to one

  20. Asymmetric transmission in prisms using structures and materials with isotropic-type dispersion.

    PubMed

    Gundogdu, Funda Tamara; Serebryannikov, Andriy E; Cakmak, A Ozgur; Ozbay, Ekmel

    2015-09-21

    It is demonstrated that strong asymmetry in transmission can be obtained at the Gaussian beam illumination for a single prism based on a photonic crystal (PhC) with isotropic-type dispersion, as well as for its analog made of a homogeneous material. Asymmetric transmission can be realized with the aid of refraction at a proper orientation of the interfaces and wedges of the prism, whereas neither contribution of higher diffraction orders nor anisotropic-type dispersion is required. Furthermore, incidence toward a prism wedge can be used for one of two opposite directions in order to obtain asymmetry. Thus, asymmetric transmission is a general property of the prism configurations, which can be obtained by using simple geometries and quite conventional materials. The obtained results show that strong asymmetry can be achieved in PhC prisms with (nearly) circular shape of equifrequency dispersion contours, in both cases associated with the index of refraction 01. For the comparison purposes, results are also presented for solid uniform non-magnetic prisms made of a material with the same value of n. It is shown in zero-loss approximation that the PhC prism and the ultralow-index material prism (0prism and the solid dielectric prism can show the same scenario at n>1. Possible contributions of scattering on the individual rods and diffraction on the wedge to the resulting mechanism are discussed. Analogs of unidirectional splitting and unidirectional deflection regimes, which are known from the studies of PhC gratings, are obtained in PhC prisms and solid uniform prisms, i.e. without higher diffraction orders.

  1. Historical Perspectives on the Epidemiology of Human Chagas Disease in Texas and Recommendations for Enhanced Understanding of Clinical Chagas Disease in the Southern United States

    PubMed Central

    Garcia, Melissa N.; Woc-Colburn, Laila; Aguilar, David; Hotez, Peter J.; Murray, Kristy O.

    2015-01-01

    Chagas disease (Trypanosoma cruzi infection) has recently been identified as an important neglected tropical disease in the United States. Anecdotally referred to as a “silent killer,” it leads to the development of potentially fatal cardiac disease in approximately 30% of those infected. In an attempt to better understand the potential of Chagas disease as a significant underlying cause of morbidity in Texas, we performed a historical literature review to assess disease burden. Human reports of triatomine bites and disease exposure were found to be prevalent in Texas. Despite current beliefs that Chagas disease is a recently emerging disease, we report historical references dating as far back as 1935. Both imported cases and autochthonous transmission contribute to the historical disease burden in Texas. We end by discussing the current knowledge gaps, and recommend priorities for advancing further epidemiologic studies and their policy implications. PMID:26540273

  2. Historical Perspectives on the Epidemiology of Human Chagas Disease in Texas and Recommendations for Enhanced Understanding of Clinical Chagas Disease in the Southern United States.

    PubMed

    Garcia, Melissa N; Woc-Colburn, Laila; Aguilar, David; Hotez, Peter J; Murray, Kristy O

    2015-11-01

    Chagas disease (Trypanosoma cruzi infection) has recently been identified as an important neglected tropical disease in the United States. Anecdotally referred to as a "silent killer," it leads to the development of potentially fatal cardiac disease in approximately 30% of those infected. In an attempt to better understand the potential of Chagas disease as a significant underlying cause of morbidity in Texas, we performed a historical literature review to assess disease burden. Human reports of triatomine bites and disease exposure were found to be prevalent in Texas. Despite current beliefs that Chagas disease is a recently emerging disease, we report historical references dating as far back as 1935. Both imported cases and autochthonous transmission contribute to the historical disease burden in Texas. We end by discussing the current knowledge gaps, and recommend priorities for advancing further epidemiologic studies and their policy implications.

  3. Urban Chagas disease in children and women in primary care centres in Buenos Aires, Argentina.

    PubMed

    Moscatelli, Guillermo; Berenstein, Ada; Tarlovsky, Ana; Siniawski, Susana; Biancardi, Miguel; Ballering, Griselda; Moroni, Samanta; Schwarcz, Marta; Hernández, Susana; García-Bournissen, Facundo; Cozzi, Andrés Espejo; Freilij, Héctor; Altcheh, Jaime

    2015-08-01

    The primary objective of this study was to estimate the prevalence of this disease in women of childbearing age and children treated at health centres in underserviced areas of the city of Buenos Aires. Demographic and Chagas disease status data were collected. Samples for Chagas disease serology were obtained on filter paper and the reactive results were confirmed with conventional samples. A total of 1,786 subjects were screened and 73 positive screening results were obtained: 17 were from children and 56 were from women. The Trypanosoma cruzi infection risk was greater in those individuals who had relatives with Chagas disease, who remember seeing kissing bugs, who were of Bolivian nationality or were born in the Argentine province of Santiago del Estero. The overall prevalence of Chagas disease was 4.08%. Due to migration, Chagas disease is currently predominantly urban. The observed prevalence requires health programme activities that are aimed at urban children and their mothers. Most children were infected congenitally, which reinforces the need for Chagas disease screening of all pregnant women and their babies in Argentina. The active search for new cases is important because the appropriate treatment in children has a high cure rate.

  4. Assessment of rectocolonic morphology and function in patients with Chagas disease in Barcelona (Spain).

    PubMed

    Salvador, Fernando; Mego, Marianela; Sánchez-Montalvá, Adrián; Morís, María; Ramírez, Kathleen; Accarino, Ana; Malagelada, Juan-Ramon; Azpiroz, Fernando; Molina, Israel

    2015-05-01

    The aim of this study was to determine the relationship between colonic symptoms, radiological abnormalities, and anorectal dysfunction in patients with Chagas disease. We performed a cross-sectional study of untreated patients diagnosed with Chagas disease. All patients were evaluated clinically (by a questionnaire for colonic symptoms based on Rome III criteria) and underwent a barium enema and anorectal manometry. A control group of patients with functional constipation and without Chagas disease was included in the study. Overall, 69 patients were included in the study: 42 patients were asymptomatic and 27 patients had abdominal symptoms according to Rome III criteria. Anorectal manometry showed a higher proportion of abnormalities in symptomatic patients than in asymptomatic ones (73% versus 21%, respectively; P < 0.0001). Megarectum was detected in a similar proportion in the different subgroups regardless of the presence of symptoms or abnormalities in anorectal functions. Among non-Chagas disease patients with functional constipation, 90% had an abnormal anorectal manometry study. Patients with Chagas disease present a high proportion of constipation with dyssynergic defecation in anorectal manometry but a low prevalence of impaired rectoanal inhibitory reflex, although these abnormalities may be nonspecific for Chagas disease. The presence of megarectum is a nonspecific finding.

  5. Chagas disease and transfusion medicine: a perspective from non-endemic countries.

    PubMed

    Angheben, Andrea; Boix, Lucia; Buonfrate, Dora; Gobbi, Federico; Bisoffi, Zeno; Pupella, Simonetta; Gandini, Giorgio; Aprili, Giuseppe

    2015-10-01

    In the last decades, increasing international migration and travel from Latin America to Europe have favoured the emergence of tropical diseases outside their "historical" boundaries. Chagas disease, a zoonosis endemic in rural areas of Central and South America represents a clear example of this phenomenon. In the absence of the vector, one of the potential modes of transmission of Chagas disease in non-endemic regions is through blood and blood products. As most patients with Chagas disease are asymptomatic and unaware of their condition, in case of blood donation they can inadvertently represent a serious threat to the safety of the blood supply in non-endemic areas. Since the first cases of transfusion-transmitted Chagas disease were described in the last years, non-endemic countries began to develop ad hoc strategies to prevent and control the spread of the infection. United States, Spain, United Kingdom and France first recognised the need for Trypanosoma cruzi screening in at-risk blood donors. In this review, we trace an up-to-date perspective on Chagas disease, describing its peculiar features, from epidemiological, pathological, clinical and diagnostic points of view. Moreover, we describe the possible transmission of Chagas disease through blood or blood products and the current strategies for its control, focusing on non-endemic areas.

  6. Chronic Chagas disease with advanced cardiac complications in Japan: Case report and literature review.

    PubMed

    Imai, Kazuo; Maeda, Takuya; Sayama, Yusuke; Osa, Morichika; Mikita, Kei; Kurane, Ichiro; Miyahira, Yasushi; Kawana, Akihiko; Miura, Sachio

    2015-10-01

    Due to the unprecedented recent increases in global migration, Chagas disease has become a global health threat and its epidemiology has drastically changed. Here we describe the first case in Japan of benznidazole treatment for chronic Chagas disease characterized by advanced cardiac complications. A 55-year-old Japanese-Brazilian woman who had previously presented with chronic heart failure was diagnosed as having Chagas disease and treated with benznidazole to prevent aggravation of her cardiac complications. However, benznidazole administration was stopped on day 56 due to severe drug-induced peripheral neuritis. Sixteen months later, her serologic test for Trypanosoma cruzi is still positive and she is being followed regularly by cardiology. Despite an estimated prevalence of over 4000 cases in Japan, only a few cases of Chagas disease have been reported. A Medline search revealed only 7 cases identified between 1995 and 2014 in Japan: in 6 cases, complications of chronic Chagas disease were apparent at the time of presentation, and sudden death occurred in 2 of these cases due to cardiac complications. This clinical case and literature review re-emphasize the urgent need to establish a surveillance network and improve the diagnostic methods and treatment framework for Chagas disease in Japan.

  7. Heart transplant recipient with history of Chagas disease and elevated panel-reactive antibodies.

    PubMed

    Davalos-Krebs, Gleidys

    2015-12-01

    Chagas disease is caused by a protozoan named Trypanosoma cruzi transmitted to humans by reduviid bugs. Severe dilated cardiomyopathy from chronic T cruzi infection is the most common finding, leading to end-stage heart failure. Heart transplant is an effective treatment for Chagas heart disease. However, T cruzi reactivation is of great concern, predisposing patients to episodes of myocarditis and rejection. A 56-year-old woman with a history of Chagas disease and elevated calculated panel reactive antibodies (CPRAs) underwent induction therapy and desensitization strategies aimed at lowering CPRAs, as elevated CPRAs have been implicated in the development of antibody-mediated rejection and reduced allograft survival. Clinical phases and signs and symptoms of Chagas disease are briefly described in an attempt to promote awareness of the disease among clinicians. In addition, serology assays approved in the United States as well as recommendations of experts on Chagas disease to assess tissues and blood specimens from endemic areas are outlined. Ultimately, the importance of ongoing surveillance is emphasized, as the future of heart transplant recipients with Chagas disease is unpredictable and the presence or reactivation of the disease requires prompt attention in an effort to prevent graft failure and death.

  8. Chagas disease and transfusion medicine: a perspective from non-endemic countries

    PubMed Central

    Angheben, Andrea; Boix, Lucia; Buonfrate, Dora; Gobbi, Federico; Bisoffi, Zeno; Pupella, Simonetta; Gandini, Giorgio; Aprili, Giuseppe

    2015-01-01

    In the last decades, increasing international migration and travel from Latin America to Europe have favoured the emergence of tropical diseases outside their “historical” boundaries. Chagas disease, a zoonosis endemic in rural areas of Central and South America represents a clear example of this phenomenon. In the absence of the vector, one of the potential modes of transmission of Chagas disease in non-endemic regions is through blood and blood products. As most patients with Chagas disease are asymptomatic and unaware of their condition, in case of blood donation they can inadvertently represent a serious threat to the safety of the blood supply in non-endemic areas. Since the first cases of transfusion-transmitted Chagas disease were described in the last years, non-endemic countries began to develop ad hoc strategies to prevent and control the spread of the infection. United States, Spain, United Kingdom and France first recognised the need for Trypanosoma cruzi screening in at-risk blood donors. In this review, we trace an up-to-date perspective on Chagas disease, describing its peculiar features, from epidemiological, pathological, clinical and diagnostic points of view. Moreover, we describe the possible transmission of Chagas disease through blood or blood products and the current strategies for its control, focusing on non-endemic areas. PMID:26513769

  9. Chagas disease and transfusion medicine: a perspective from non-endemic countries.

    PubMed

    Angheben, Andrea; Boix, Lucia; Buonfrate, Dora; Gobbi, Federico; Bisoffi, Zeno; Pupella, Simonetta; Gandini, Giorgio; Aprili, Giuseppe

    2015-10-01

    In the last decades, increasing international migration and travel from Latin America to Europe have favoured the emergence of tropical diseases outside their "historical" boundaries. Chagas disease, a zoonosis endemic in rural areas of Central and South America represents a clear example of this phenomenon. In the absence of the vector, one of the potential modes of transmission of Chagas disease in non-endemic regions is through blood and blood products. As most patients with Chagas disease are asymptomatic and unaware of their condition, in case of blood donation they can inadvertently represent a serious threat to the safety of the blood supply in non-endemic areas. Since the first cases of transfusion-transmitted Chagas disease were described in the last years, non-endemic countries began to develop ad hoc strategies to prevent and control the spread of the infection. United States, Spain, United Kingdom and France first recognised the need for Trypanosoma cruzi screening in at-risk blood donors. In this review, we trace an up-to-date perspective on Chagas disease, describing its peculiar features, from epidemiological, pathological, clinical and diagnostic points of view. Moreover, we describe the possible transmission of Chagas disease through blood or blood products and the current strategies for its control, focusing on non-endemic areas. PMID:26513769

  10. Urban Chagas disease in children and women in primary care centres in Buenos Aires, Argentina

    PubMed Central

    Moscatelli, Guillermo; Berenstein, Ada; Tarlovsky, Ana; Siniawski, Susana; Biancardi, Miguel; Ballering, Griselda; Moroni, Samanta; Schwarcz, Marta; Hernández, Susana; García-Bournissen, Facundo; Cozzi, Andrés Espejo; Freilij, Héctor; Altcheh, Jaime

    2015-01-01

    The primary objective of this study was to estimate the prevalence of this disease in women of childbearing age and children treated at health centres in underserviced areas of the city of Buenos Aires. Demographic and Chagas disease status data were collected. Samples for Chagas disease serology were obtained on filter paper and the reactive results were confirmed with conventional samples. A total of 1,786 subjects were screened and 73 positive screening results were obtained: 17 were from children and 56 were from women. The Trypanosoma cruzi infection risk was greater in those individuals who had relatives with Chagas disease, who remember seeing kissing bugs, who were of Bolivian nationality or were born in the Argentine province of Santiago del Estero. The overall prevalence of Chagas disease was 4.08%. Due to migration, Chagas disease is currently predominantly urban. The observed prevalence requires health programme activities that are aimed at urban children and their mothers. Most children were infected congenitally, which reinforces the need for Chagas disease screening of all pregnant women and their babies in Argentina. The active search for new cases is important because the appropriate treatment in children has a high cure rate. PMID:26222020

  11. Urban Chagas disease in children and women in primary care centres in Buenos Aires, Argentina.

    PubMed

    Moscatelli, Guillermo; Berenstein, Ada; Tarlovsky, Ana; Siniawski, Susana; Biancardi, Miguel; Ballering, Griselda; Moroni, Samanta; Schwarcz, Marta; Hernández, Susana; García-Bournissen, Facundo; Cozzi, Andrés Espejo; Freilij, Héctor; Altcheh, Jaime

    2015-08-01

    The primary objective of this study was to estimate the prevalence of this disease in women of childbearing age and children treated at health centres in underserviced areas of the city of Buenos Aires. Demographic and Chagas disease status data were collected. Samples for Chagas disease serology were obtained on filter paper and the reactive results were confirmed with conventional samples. A total of 1,786 subjects were screened and 73 positive screening results were obtained: 17 were from children and 56 were from women. The Trypanosoma cruzi infection risk was greater in those individuals who had relatives with Chagas disease, who remember seeing kissing bugs, who were of Bolivian nationality or were born in the Argentine province of Santiago del Estero. The overall prevalence of Chagas disease was 4.08%. Due to migration, Chagas disease is currently predominantly urban. The observed prevalence requires health programme activities that are aimed at urban children and their mothers. Most children were infected congenitally, which reinforces the need for Chagas disease screening of all pregnant women and their babies in Argentina. The active search for new cases is important because the appropriate treatment in children has a high cure rate. PMID:26222020

  12. Chagas disease in the United States: a cause for concern in Louisiana?

    PubMed

    Diaz, James H

    2007-01-01

    Chagas disease, or American trypanosomiasis, is an arthropod-borne protozoan infectious disease, hyperendemic throughout Latin America, caused by Trypanosoma cruzi, and transmitted to man by reduviid or kissing bugs. Throughout the Americas, Chagas disease shares many life cycle features with malaria, including transmission of infectious stages by local arthropods, exacerbation or reactivation of subclinical infections by immunosuppression (particularly HIV/AIDS) and pregnancy, and both transplacental and transfusion-related transmission. Although most cases of Chagas disease in the United States (US) are imported, significant numbers of Latin American immigrants contribute to the US blood supply and donate cadaveric tissues and organs for human transplantation, thus increasing the risks of both transfusion and transplantation-transmitted Chagas disease from unscreened blood products and transplantable tissues and organs. In addition, the risks of local reduviid bug-transmitted autochthonous or indigenous Chagas disease are also increasing as more immigrant workers enter the displaced populations of the Gulf South, including Louisiana, to assist in rebuilding efforts after Hurricanes Katrina and Rita. Although screening donated blood products for malaria remains impractical, consideration should now be given to serologically screening all donated blood and organs for Chagas disease in the US, as in most countries of Latin America, especially in high risk areas of California and the southern US, including Louisiana.

  13. Heart transplant recipient with history of Chagas disease and elevated panel-reactive antibodies.

    PubMed

    Davalos-Krebs, Gleidys

    2015-12-01

    Chagas disease is caused by a protozoan named Trypanosoma cruzi transmitted to humans by reduviid bugs. Severe dilated cardiomyopathy from chronic T cruzi infection is the most common finding, leading to end-stage heart failure. Heart transplant is an effective treatment for Chagas heart disease. However, T cruzi reactivation is of great concern, predisposing patients to episodes of myocarditis and rejection. A 56-year-old woman with a history of Chagas disease and elevated calculated panel reactive antibodies (CPRAs) underwent induction therapy and desensitization strategies aimed at lowering CPRAs, as elevated CPRAs have been implicated in the development of antibody-mediated rejection and reduced allograft survival. Clinical phases and signs and symptoms of Chagas disease are briefly described in an attempt to promote awareness of the disease among clinicians. In addition, serology assays approved in the United States as well as recommendations of experts on Chagas disease to assess tissues and blood specimens from endemic areas are outlined. Ultimately, the importance of ongoing surveillance is emphasized, as the future of heart transplant recipients with Chagas disease is unpredictable and the presence or reactivation of the disease requires prompt attention in an effort to prevent graft failure and death. PMID:26645921

  14. Separation of multiple images via directional guidance using structured prism and pyramid arrays.

    PubMed

    Lee, Hyemin; Seo, Hyein; Kang, Sunghwan; Yoon, Hyunsik

    2016-09-01

    We propose a new concept of separating images through a directional guide of multi-visuals by using structured prism or pyramid arrays. By placing prism arrays onto two different image arrays, the two collective images below the facets are guided to different directions. Using optical calculations, we identify a condition for successful image separation. Transparent pyramid arrays are used to separate four images into four directions. The direction of refracted rays can be controlled by the refractive index of prisms and liquid filled into the voids. In addition, the images can be switched by stretching and releasing an elastomeric prism array. PMID:27607698

  15. Separation of multiple images via directional guidance using structured prism and pyramid arrays.

    PubMed

    Lee, Hyemin; Seo, Hyein; Kang, Sunghwan; Yoon, Hyunsik

    2016-09-01

    We propose a new concept of separating images through a directional guide of multi-visuals by using structured prism or pyramid arrays. By placing prism arrays onto two different image arrays, the two collective images below the facets are guided to different directions. Using optical calculations, we identify a condition for successful image separation. Transparent pyramid arrays are used to separate four images into four directions. The direction of refracted rays can be controlled by the refractive index of prisms and liquid filled into the voids. In addition, the images can be switched by stretching and releasing an elastomeric prism array.

  16. Reactivation of Chagas Disease: Implications for Global Health.

    PubMed

    Perez, Catherine J; Lymbery, Alan J; Thompson, R C Andrew

    2015-11-01

    Reactivation of Chagas Disease (CD) is a global public health issue. Reactivation of disease can affect the management of CD and its clinical outcome, adding pressure to global health systems because it exacerbates symptoms, leading to misdiagnosis and delays in the administration of correct treatments. Concurrent infections complicate the issue of reactivation, because there are various parasites and disease treatment regimens that are able to influence or suppress the immune system of the host, reactivating disease within infected individuals. The effect of delayed symptoms of chronic CD and the potential for disease reactivation are of great importance to nonendemic regions of the world, where knowledge about CD is lacking and the potential for vectorial transmission is not known.

  17. [Science as a profession: an interview with Carlos Chagas Filho].

    PubMed

    Chagas Filho, Carlos

    2012-06-01

    The editing of this interview focuses on aspects of the extensive professional career of Carlos Chagas Filho, who was the founder of the Instituto de Biofísica of the Universidade do Brasil, currently the Universidade Federal do Rio de Janeiro. It highlights the scientific and political role he played in Brazilian science and on the international scene. His memoirs include his experience at the Instituto Oswaldo Cruz, where he began his scientific training; the efforts to create the Laboratório de Física Biológica, succeeded by the Instituto de Biofísica; his work on the Conselho Nacional de Pesquisas and the Academia Brasileira de Ciências; the part he played at the United Nations Educational, Scientific and Cultural Organization; his time as president of the Pontifical Academy of Sciences of the Vatican, which led him to ponder questions about the relationship between science and religion.

  18. Membranous nephropathy PLA2R+ associated with Chagas disease

    PubMed Central

    Silva, Vanessa dos Santos; Viero, Rosa Marlene

    2015-01-01

    Chagas disease (CD) — a tropical parasitic disease caused by the protozoan Trypanosoma cruzi — is a major health problem in Latin America. The immune response against the parasite is responsible for chronic CD lesions. Currently, there are no reports of an association between CD and membranous nephropathy (MN). The detection of the phospholipase A2 receptor (PLA2R) as a target antigen in idiopathic MN can improve the differential diagnosis of primary and secondary forms of MN. The authors report the case of a male patient with positive serology for CD who presented sudden death and underwent autopsy. Histological sections of the heart showed multifocal inflammatory infiltrate composed mainly of mononuclear cells, leading to myocardiocytes necrosis and interstitial fibrosis. The kidneys showed a MN with positive expression for PLA2R. As far as we know, this is the first report of a case of primary MN in a patient with CD, with severe chronic cardiomyopathy and heart failure. PMID:26558244

  19. Agrochemicals against Malaria, Sleeping Sickness, Leishmaniasis and Chagas Disease

    PubMed Central

    Witschel, Matthias; Rottmann, Matthias; Kaiser, Marcel; Brun, Reto

    2012-01-01

    In tropical regions, protozoan parasites can cause severe diseases with malaria, leishmaniasis, sleeping sickness, and Chagas disease standing in the forefront. Many of the drugs currently being used to treat these diseases have been developed more than 50 years ago and can cause severe adverse effects. Above all, resistance to existing drugs is widespread and has become a serious problem threatening the success of control measures. In order to identify new antiprotozoal agents, more than 600 commercial agrochemicals have been tested on the pathogens causing the above mentioned diseases. For all of the pathogens, compounds were identified with similar or even higher activities than the currently used drugs in applied in vitro assays. Furthermore, in vivo activity was observed for the fungicide/oomyceticide azoxystrobin, and the insecticide hydramethylnon in the Plasmodium berghei mouse model, and for the oomyceticide zoxamide in the Trypanosoma brucei rhodesiense STIB900 mouse model, respectively. PMID:23145187

  20. Membranous nephropathy PLA2R+ associated with Chagas disease.

    PubMed

    Xavier-Júnior, José Cândido Caldeira; Silva, Vanessa Dos Santos; Viero, Rosa Marlene

    2015-01-01

    Chagas disease (CD) - a tropical parasitic disease caused by the protozoan Trypanosoma cruzi - is a major health problem in Latin America. The immune response against the parasite is responsible for chronic CD lesions. Currently, there are no reports of an association between CD and membranous nephropathy (MN). The detection of the phospholipase A2 receptor (PLA2R) as a target antigen in idiopathic MN can improve the differential diagnosis of primary and secondary forms of MN. The authors report the case of a male patient with positive serology for CD who presented sudden death and underwent autopsy. Histological sections of the heart showed multifocal inflammatory infiltrate composed mainly of mononuclear cells, leading to myocardiocytes necrosis and interstitial fibrosis. The kidneys showed a MN with positive expression for PLA2R. As far as we know, this is the first report of a case of primary MN in a patient with CD, with severe chronic cardiomyopathy and heart failure.

  1. Epicuticular lipids induce aggregation in Chagas disease vectors

    PubMed Central

    Figueiras, Alicia N Lorenzo; Girotti, Juan R; Mijailovsky, Sergio J; Juárez, M Patricia

    2009-01-01

    Background The triatomine bugs are vectors of the protozoan parasite Trypanosoma cruzi, the causative agent of Chagas disease. Aggregation behavior plays an important role in their survival by facilitating the location of refuges and cohesion of aggregates, helping to keep them safely assembled into shelters during daylight time, when they are vulnerable to predators. There are evidences that aggregation is mediated by thigmotaxis, by volatile cues from their faeces, and by hexane-extractable contact chemoreceptive signals from their cuticle surface. The epicuticular lipids of Triatoma infestans include a complex mixture of hydrocarbons, free and esterified fatty acids, alcohols, and sterols. Results We analyzed the response of T. infestans fifth instar nymphs after exposure to different amounts either of total epicuticular lipid extracts or individual lipid fractions. Assays were performed in a circular arena, employing a binary choice test with filter papers acting as aggregation attractive sites; papers were either impregnated with a hexane-extract of the total lipids, or lipid fraction; or with the solvent. Insects were significantly aggregated around papers impregnated with the epicuticular lipid extracts. Among the lipid fractions separately tested, only the free fatty acid fraction promoted significant bug aggregation. We also investigated the response to different amounts of selected fatty acid components of this fraction; receptiveness varied with the fatty acid chain length. No response was elicited by hexadecanoic acid (C16:0), the major fatty acid component. Octadecanoic acid (C18:0) showed a significant assembling effect in the concentration range tested (0.1 to 2 insect equivalents). The very long chain hexacosanoic acid (C26:0) was significantly attractant at low doses (≤ 1 equivalent), although a repellent effect was observed at higher doses. Conclusion The detection of contact aggregation pheromones has practical application in Chagas disease

  2. Overland Tidal Power Generation Using Modular Tidal Prism

    SciTech Connect

    Khangaonkar, Tarang; Yang, Zhaoqing; Geerlofs, Simon H.; Copping, Andrea

    2010-03-01

    Naturally occurring sites with sufficient kinetic energy suitable for tidal power generation with sustained currents > 1 to 2 m/s are relatively rare. Yet sites with greater than 3 to 4 m of tidal range are relatively common around the U.S. coastline. Tidal potential does exist along the shoreline but is mostly distributed, and requires an approach which allows trapping and collection to also be conducted in a distributed manner. In this paper we examine the feasibility of generating sustainable tidal power using multiple nearshore tidal energy collection units and present the Modular Tidal Prism (MTP) basin concept. The proposed approach utilizes available tidal potential by conversion into tidal kinetic energy through cyclic expansion and drainage from shallow modular manufactured overland tidal prisms. A preliminary design and configuration of the modular tidal prism basin including inlet channel configuration and basin dimensions was developed. The unique design was shown to sustain momentum in the penstocks during flooding as well as ebbing tidal cycles. The unstructured-grid finite volume coastal ocean model (FVCOM) was used to subject the proposed design to a number of sensitivity tests and to optimize the size, shape and configuration of MTP basin for peak power generation capacity. The results show that an artificial modular basin with a reasonable footprint (≈ 300 acres) has the potential to generate 10 to 20 kw average energy through the operation of a small turbine located near the basin outlet. The potential of generating a total of 500 kw to 1 MW of power through a 20 to 40 MTP basin tidal power farms distributed along the coastline of Puget Sound, Washington, is explored.

  3. The PRISM palaeoclimate reconstruction and Pliocene sea-surface temperature

    USGS Publications Warehouse

    Dowsett, H.J.

    2007-01-01

    In this paper, I present a summary of the Pliocene Research, Interpretation and Synoptic Mapping (PRISM) palaeoenvironmental reconstruction, with emphasis on its historical development and range of boundary condition datasets. Sea-surface temperature (SST), sea level, sea ice, land cover (vegetation and ice) and topography are discussed as well as many of the assumptions required to create an integrated global-scale reconstruction. New multiproxy research shows good general agreement on the magnitude of mid-Pliocene SST warming. Future directions, including maximum and minimum SST analyses and deep ocean temperature estimates aimed at a full three-dimensional reconstruction, are presented. ?? The Micropalaeontological Society 2007.

  4. Ultrafine Metal-Organic Right Square Prism Shaped Nanowires.

    PubMed

    Otake, Ken-Ichi; Otsubo, Kazuya; Sugimoto, Kunihisa; Fujiwara, Akihiko; Kitagawa, Hiroshi

    2016-05-23

    We report the structural design and control of electronic states of a new series of ultrafine metal-organic right square prism-shaped nanowires. These nanowires have a very small inner diameter of about 2.0 Å, which is larger than hydrogen and similar to xenon atomic diameters. The electronic states of nanowires can be widely controlled by substitution of structural components. Moreover, the platinum homometallic nanowire shows a 100 times higher proton conductivity than a palladium/platinum heterometallic one depending on the electronic states.

  5. Sealed One Piece Battery Having A Prism Shape Container

    DOEpatents

    Verhoog, Roelof; Barbotin, Jean-Loup

    2000-03-28

    A sealed one-piece battery having a prism-shaped container including: a tank consisting of a single plastic material, a member fixed and sealed to the tank and to partitions on the side of the tank opposite the transverse wall to seal the tank, two flanges fixed and sealed to longitudinal walls defining flow compartments for a heat-conducting fluid, and two tubes on the transverse wall of the tank forming an inlet and an outlet for fluid common to the compartments.

  6. Asymmetrical prism for beam shaping of laser diode stacks.

    PubMed

    Zeng, Xiaodong; Cao, Changqing; An, Yuying

    2005-09-10

    A beam-shaping scheme for a laser diode stack to obtain a flattop output intensity profile is proposed. The shaping element consists of an asymmetrical glass prism. The large divergence-angle compression in the direction perpendicular to the junction plane and the small divergence-angle expansion in the parallel direction are performed simultaneously by a single shaping element. The transformation characteristics are presented, and the optimization performance is investigated based on the ray-tracing method. Analysis shows that a flattop intensity profile can be obtained. This beam-shaping system can be fabricated easily and has a large alignment tolerance.

  7. Ultrafine Metal-Organic Right Square Prism Shaped Nanowires.

    PubMed

    Otake, Ken-Ichi; Otsubo, Kazuya; Sugimoto, Kunihisa; Fujiwara, Akihiko; Kitagawa, Hiroshi

    2016-05-23

    We report the structural design and control of electronic states of a new series of ultrafine metal-organic right square prism-shaped nanowires. These nanowires have a very small inner diameter of about 2.0 Å, which is larger than hydrogen and similar to xenon atomic diameters. The electronic states of nanowires can be widely controlled by substitution of structural components. Moreover, the platinum homometallic nanowire shows a 100 times higher proton conductivity than a palladium/platinum heterometallic one depending on the electronic states. PMID:27080935

  8. Deformation of the Nankai Trough inner accretionary prism: The role of inherited structures

    NASA Astrophysics Data System (ADS)

    Boston, Brian; Moore, Gregory F.; Jurado, María. José; Sone, Hiroki

    2016-02-01

    Accretionary prisms commonly grow seaward, with the strata of the inner prism consisting of older, previously accreted outer prism rocks overlain by thick fore-arc basin strata. We focus on the Nankai Trough inner accretionary prism using three-dimensional (3-D) seismic data and logging data from the Integrated Ocean Drilling Program (IODP). We update the 3-D seismic volume using well velocity data to better constrain deeper horizons. Interpretation of these horizons reveals multiple folds with axial surfaces that strike near parallel to modern outer prism thrust faults, and we interpret that these folds formed as a result of thrust faulting. Reactivation of one inner prism thrust fault continued until at least ˜0.44 Ma, after the modern fore-arc basin formed, indicating that the inner prism had continued deformation until that time. Structural restorations of these folded seismic horizons demonstrate that ˜580 m of slip occurred on this steeply dipping reactivated thrust after fore-arc basin formation. Structural interpretation and analysis of logging-while-drilling data, including borehole images, in the deep inner prism revealed intense deformation of a generally homogenous lithology characterized by bedding that dips steeply (60°-90°), intersected by faults and fractures that have a range of dips and densities. Our study of the deep Kumano Basin provides new insights into the structure of the inner prism and reveals that although the inner prism has partially preserved inherited outer prism structures, these older folds and faults are steeply rotated and cut by multiple fracture populations during subsequent deformation.

  9. A Pilot Study of Perceptual-Motor Training for Peripheral Prisms

    PubMed Central

    Houston, Kevin E.; Bowers, Alex R.; Fu, Xianping; Liu, Rui; Goldstein, Robert B.; Churchill, Jeff; Wiegand, Jean-Paul; Soo, Tim; Tang, Qu; Peli, Eli

    2016-01-01

    Purpose Peripheral prisms (p-prisms) shift peripheral portions of the visual field of one eye, providing visual field expansion for patients with hemianopia. However, patients rarely show adaption to the shift, incorrectly localizing objects viewed within the p-prisms. A pilot evaluation of a novel computerized perceptual-motor training program aiming to promote p-prism adaption was conducted. Methods Thirteen patients with hemianopia fitted with 57Δ oblique p-prisms completed the training protocol. They attended six 1-hour visits reaching and touching peripheral checkerboard stimuli presented over videos of driving scenes while fixating a central target. Performance was measured at each visit and after 3 months. Results There was a significant reduction in touch error (P = 0.01) for p-prism zone stimuli from pretraining median of 16.6° (IQR 12.1°–19.6°) to 2.7° ( IQR 1.0°–8.5°) at the end of training. P-prism zone reaction times did not change significantly with training (P > 0.05). P-prism zone detection improved significantly (P = 0.01) from a pretraining median 70% (IQR 50%–88%) to 95% at the end of training (IQR 73%–98%). Three months after training improvements had regressed but performance was still better than pretraining. Conclusions Improved pointing accuracy for stimuli detected in prism-expanded vision of patients with hemianopia wearing 57Δ oblique p-prisms is possible and training appears to further improve detection. Translational Relevance This is the first use of this novel software to train adaptation of visual direction in patients with hemianopia wearing peripheral prisms. PMID:26933522

  10. The PRISM (Pliocene Palaeoclimate) reconstruction: Time for a paradigm shift

    USGS Publications Warehouse

    Dowsett, Harry J.; Robinson, Marci M.; Stoll, Danielle K.; Foley, Kevin M.; Johnson, Andrew L. A.; Williams, Mark; Riesselman, Christina

    2013-01-01

    Global palaeoclimate reconstructions have been invaluable to our understanding of the causes and effects of climate change, but single-temperature representations of the oceanic mixed layer for data–model comparisons are outdated, and the time for a paradigm shift in marine palaeoclimate reconstruction is overdue. The new paradigm in marine palaeoclimate reconstruction stems the loss of valuable climate information and instead presents a holistic and nuanced interpretation of multi-dimensional oceanographic processes and responses. A wealth of environmental information is hidden within the US Geological Survey's Pliocene Research,Interpretation and Synoptic Mapping (PRISM) marine palaeoclimate reconstruction, and we introduce here a plan to incorporate all valuable climate data into the next generation of PRISM products. Beyond the global approach and focus, we plan to incorporate regional climate dynamics with emphasis on processes, integrating multiple environmental proxies wherever available in order to better characterize the mixed layer, and developing a finer time slice within the Mid-Piacenzian Age of the Pliocene, complemented by underused proxies that offer snapshots into environmental conditions. The result will be a proxy-rich, temporally nested, process-oriented approach in a digital format—a relational database with geographic information system capabilities comprising a three-dimensional grid representing the surface layer, with a plethora of data in each cell.

  11. Thermal camouflage pattern prediction using PRISM and PMO

    NASA Astrophysics Data System (ADS)

    BoBo, Geralyn; Gonda, Teresa G.; Bacon, Fred W.

    2001-09-01

    This paper describes the initial phase of an evaluation study on the performance of PMO, the Paint Map Optimizer, for long wave infrared (LWIR) modeling. In this phase, we will evaluate using PRIMS, the Physically Reasonable Infrared Signature Modeler, to predict the thermal signature of a simplified tank geometry, and then PMO to predict the optimal thermal camouflage pattern from a range of emissivities in a given scenario. Prism is a thermal modeling code that has been used extensively to model thermal signatures of military ground vehicles. PMO was developed by Aerodyne Research to provide a computer-aided design tool for camouflage pattern design and optimization in a given scenario and a given band for the US Army Aviation Technology Directorate, AATD. At the end of this phase, we hope to determine the basic effectiveness of the process and identify areas of improvement if necessary. The geometry was modeled in PRISM. which output the thermal signature for input into PMO. The optimizer was used to predict the thermal camouflage pattern in the 8-12micrometers IR band for a range of emissivities with the geometry in three different locations in the background image.

  12. Spectra of Eta Carina from Objective Prism Photographic Plates

    NASA Astrophysics Data System (ADS)

    Cline, J. Donald; Castelaz, M.; Barker, T.

    2008-05-01

    Brightness and spectral variations of Eta Carina occur over a 5.5 year cycle. Emission lines were observed to fade in 1948, 1962, 1981, 1987, and 1992 (Damineli 1996, ApJ, 460, L49), and 1997 (Eta Carinae at the Millennium, ASP Conf. Ser. 179, ed. J.A. Morse, R.M. Humphreys, and A. Damineli). Gaps in the observation of spectra occur in 1970 and 1975 when two other such occurrences of the 5.5 year cycle were expected. Objective prism photographic plates of Eta Carina were found in the Astronomical Photographic Data Archive located at Pisgah Astronomical Research Institute. The plates belong to the University of Michigan survey (Houk 1978, Michigan Catalogue of Two-dimensional Spectral Types for the HD Stars). One plate, IN emulsion + RG1 filter, was taken on 1968 July 4 UT. The other plate, IIaO emulsion, was taken on 1972 March 12 UT. These plates were taken between the 5.5 year cyclic events of 1970 and 1975 and therefore represent the usual emission line spectra. The spectrum of Eta Car was extracted from each of the objective prism plates and will be presented.

  13. The PRISM (Pliocene palaeoclimate) reconstruction: time for a paradigm shift.

    PubMed

    Dowsett, Harry J; Robinson, Marci M; Stoll, Danielle K; Foley, Kevin M; Johnson, Andrew L A; Williams, Mark; Riesselman, Christina R

    2013-10-28

    Global palaeoclimate reconstructions have been invaluable to our understanding of the causes and effects of climate change, but single-temperature representations of the oceanic mixed layer for data-model comparisons are outdated, and the time for a paradigm shift in marine palaeoclimate reconstruction is overdue. The new paradigm in marine palaeoclimate reconstruction stems the loss of valuable climate information and instead presents a holistic and nuanced interpretation of multi-dimensional oceanographic processes and responses. A wealth of environmental information is hidden within the US Geological Survey's Pliocene Research, Interpretation and Synoptic Mapping (PRISM) marine palaeoclimate reconstruction, and we introduce here a plan to incorporate all valuable climate data into the next generation of PRISM products. Beyond the global approach and focus, we plan to incorporate regional climate dynamics with emphasis on processes, integrating multiple environmental proxies wherever available in order to better characterize the mixed layer, and developing a finer time slice within the Mid-Piacenzian Age of the Pliocene, complemented by underused proxies that offer snapshots into environmental conditions. The result will be a proxy-rich, temporally nested, process-oriented approach in a digital format-a relational database with geographic information system capabilities comprising a three-dimensional grid representing the surface layer, with a plethora of data in each cell.

  14. Standardization of motion sickness induced by left-right and up-down reversing prisms

    NASA Technical Reports Server (NTRS)

    Reschke, M. F.; Vanderploeg, J. M.; Brumley, E. A.; Kolafa, J. J.; Wood, S. J.

    1990-01-01

    Reversing prisms are known to produce symptoms of motion sickness, and have been used to provide a chronic stimulus for training subjects on symptom recognition and regulation. However, testing procedures with reversing prisms have not been standardized. A set of procedures were evaluated which could be standardized using prisms for provocation and to compare the results between Right/Left Reversing Prisms (R/L-RP) and Up/Down Reversing Prisms (U/D-RP). Fifteen subjects were tested with both types of prisms using a self paced walking course throughout the laboratory with work stations established at specified intervals. The work stations provided tasks requiring eye-hand-foot coordination and various head movements. Comparisons were also made between these prism tests and two other standardized susceptibility tests, the KC-135 parabolic static chair test and the Staircase Velocity Motion Test (SVMT). Two different types of subjective symptom reports were compared. The R/L-RP were significantly more provocative than the U/D-RP. The incidence of motion sickness symptoms for the R/L-RP was similar to the KC-135 parabolic static chair test. Poor correlations were found between the prism tests and the other standardized susceptibility tests, which might indicate that different mechanisms are involved in provoking motion sickness for these different tests.

  15. Hierarchically triangular prism structured Co3O4: Self-supported fabrication and photocatalytic property

    EPA Science Inventory

    The formation of ammonium cobalt (II) phosphate was utilized to synthesize unprecedented 3D structures of Co3O4, triangular prisms and trunk-like structures, via a self-supported and organics-free method. The length of a triangular side of the prepared 3D triangular prisms is ~1...

  16. Electron sharing and anion-π recognition in molecular triangular prisms.

    PubMed

    Schneebeli, Severin T; Frasconi, Marco; Liu, Zhichang; Wu, Yilei; Gardner, Daniel M; Strutt, Nathan L; Cheng, Chuyang; Carmieli, Raanan; Wasielewski, Michael R; Stoddart, J Fraser

    2013-12-01

    Stacking on a full belly: Triangular molecular prisms display electron sharing among their triangularly arranged naphthalenediimide (NDI) redox centers. Their electron-deficient cavities encapsulate linear triiodide anions, leading to the formation of supramolecular helices in the solid state. Chirality transfer is observed from the six chiral centers of the filled prisms to the single-handed helices.

  17. Investigating First Year Elementary Mathematics Teacher Education Students' Knowledge of Prism

    ERIC Educational Resources Information Center

    Bozkurt, Ali; Koc, Yusuf

    2012-01-01

    The purpose of this study was to investigate first year elementary mathematics teacher education students' knowledge of prism. For this goal, the participants were asked to define the geometric concept of prism. The participants were 158 first year elementary mathematics teacher education students from a public university in Southern Turkey. The…

  18. Prism Foil from an LCD Monitor as a Tool for Teaching Introductory Optics

    ERIC Educational Resources Information Center

    Planinsic, Gorazd; Gojkosek, Mihael

    2011-01-01

    Transparent prism foil is part of a backlight system in LCD monitors that are widely used today. This paper describes the optical properties of the prism foil and several pedagogical applications suitable for undergraduate introductory physics level. Examples include experiments that employ refraction, total internal reflection, diffraction and…

  19. Impact of high power and angle of incidence on prism corrections for visual field loss

    NASA Astrophysics Data System (ADS)

    Jung, Jae-Hyun; Peli, Eli

    2014-06-01

    Prism distortions and spurious reflections are not usually considered when prescribing prisms to compensate for visual field loss due to homonymous hemianopia. Distortions and reflections in the high-power Fresnel prisms used in peripheral prism placement can be considerable, and the simplifying assumption that prism deflection power is independent of angle of incidence into the prisms results in substantial errors. We analyze the effects of high prism power and incidence angle on the field expansion, size of the apical scotomas, and image compression/expansion. We analyze and illustrate the effects of reflections within the Fresnel prisms, primarily due to reflections at the bases, and secondarily due to surface reflections. The strength and location of these effects differs materially depending on whether the serrated prismatic surface is placed toward or away from the eye, and this affects the contribution of the reflections to visual confusion, diplopia, false alarms, and loss of contrast. We conclude with suggestions for controlling and mitigating these effects in clinical practice.

  20. Electron sharing and anion-π recognition in molecular triangular prisms.

    PubMed

    Schneebeli, Severin T; Frasconi, Marco; Liu, Zhichang; Wu, Yilei; Gardner, Daniel M; Strutt, Nathan L; Cheng, Chuyang; Carmieli, Raanan; Wasielewski, Michael R; Stoddart, J Fraser

    2013-12-01

    Stacking on a full belly: Triangular molecular prisms display electron sharing among their triangularly arranged naphthalenediimide (NDI) redox centers. Their electron-deficient cavities encapsulate linear triiodide anions, leading to the formation of supramolecular helices in the solid state. Chirality transfer is observed from the six chiral centers of the filled prisms to the single-handed helices. PMID:24227594

  1. Diffraction theory applied to X-ray imaging with clessidra prism array lenses.

    PubMed

    De Caro, Liberato; Jark, Werner

    2008-03-01

    Clessidra (hourglass) lenses, i.e. two large prisms each composed of smaller identical prisms or prism-like objects, can focus X-rays. As these lenses have a periodic structure perpendicular to the incident radiation, they will diffract the beam like a diffraction grating. Refraction in the prisms is responsible for blazing, i.e. for the concentration of the diffracted intensity into only a few diffraction peaks. It is found that the diffraction of coherent radiation in clessidra lenses needs to be treated in the Fresnel, or near-field, regime. Here, diffraction theory is applied appropriately to the clessidra structure in order to show that blazing in a perfect structure with partly curved prisms can indeed concentrate the diffracted intensity into only one peak. When the lens is entirely composed of identical perfect prisms, small secondary peaks are found. Nevertheless, the loss in intensity in the central peak will not lead to any significant widening of this peak. Clessidras with perfect prisms illuminated by full coherent X-ray radiation can then provide spatial resolutions, which are consistent with the increased aperture, and which are far below the height of the single small prisms.

  2. A unit structure Rochon prism based on the extraordinary refraction of uniaxial birefringent crystals.

    PubMed

    Wu, Wendi; Wu, Fuquan; Shi, Meng; Su, Fufang; Han, Peigao; Ma, Lili

    2013-06-01

    Based on the Fermat's principle, the universal theory of refraction and reflection of extraordinary rays (e-rays) in the uniaxial crystal is formulated. Using this theory, a new unit structure prism is designed, and its properties are studied. Based on the theoretical results, such a prism is achieved experimentally by using the Iceland crystal. In both theoretical and experimental studies, this new prism shows excellent polarization splitting performances such as big and adjustable splitting angle, comparing to the conventional Rochon prism. For the sample prism with the optical axis angle of 45°, the splitting angle reaches 19.8°in the normal incidence, and the maximum splitting angle reaches 28.44° while the incidence angle is -4°. PMID:23736569

  3. ePRISM: A case study in multiple proxy and mixed temporal resolution integration

    USGS Publications Warehouse

    Robinson, Marci M.; Dowsett, Harry J.

    2010-01-01

    As part of the Pliocene Research, Interpretation and Synoptic Mapping (PRISM) Project, we present the ePRISM experiment designed I) to provide climate modelers with a reconstruction of an early Pliocene warm period that was warmer than the PRISM interval (similar to 3.3 to 3.0 Ma), yet still similar in many ways to modern conditions and 2) to provide an example of how best to integrate multiple-proxy sea surface temperature (SST) data from time series with varying degrees of temporal resolution and age control as we begin to build the next generation of PRISM, the PRISM4 reconstruction, spanning a constricted time interval. While it is possible to tie individual SST estimates to a single light (warm) oxygen isotope event, we find that the warm peak average of SST estimates over a narrowed time interval is preferential for paleoclimate reconstruction as it allows for the inclusion of more records of multiple paleotemperature proxies.

  4. Controlling Orientational Order in 1-D Assemblies of Multivalent Triangular Prisms.

    PubMed

    Kohlstedt, Kevin L; Olvera de la Cruz, Monica; Schatz, George C

    2013-01-01

    Multivalent nanostructures are becoming an increasingly important player in the self-assembly of supramolecular lattices. Understanding the role that shape plays in the coordination of the assemblies is crucial for the functional response of the material. We develop a simple design rule for the assembly of multivalent Au triangular nanoprisms into 1-D ordered arrays based on both the length of the valent DNA and the aspect ratio of the prism. Using MD simulations, we describe an order parameter that captures the short-range order of the assembly controlled by the design parameters. The order parameter shows that even short chains (N = 4) of prisms have a high degree of orientational order that transitions to no orientational order when the DNA length is similar to the prism length. Unlike isotropic polyvalent assemblies, we find that the highly oriented chains of prisms lose orientational order in discrete steps during melting as the prisms in the arrays dissociate.

  5. The use of prisms for vision rehabilitation after macular function loss: an evidence-based review.

    PubMed

    Markowitz, Samuel N; Reyes, Sophia V; Sheng, Li

    2013-05-01

    To determine the efficacy of prisms used for redirection of incoming images towards the peripheral retina in cases with macular function loss. Meta-analysis of published work reporting outcomes from interventions using prisms was performed. The primary outcome measure selected for analysis was visual acuity (VA) used for viewing distance targets. Pooled data from 449 cases where prisms were prescribed for wearing in distance glasses were analysed. Visual acuity was better after using prisms (1.05 versus 0.89 logMAR units, p < 0.044). Mean effect size for improving VA was 79 bigger than the effect size calculated for the control group (0.158 versus 0.002). Most patients (76%) reported compliance with the therapy and also reported other benefits directly derived from the realized VA improvement. Published studies collectively offer positive evidence in support of using prisms for low vision rehabilitation after macular function loss. Further research is required to reach definitive binding conclusions.

  6. Light propagation tuned by periodic junction-prisms within well-faceted ZnO fibers.

    PubMed

    Huang, Lisheng; Pu, Lin; Shi, Yi; Zhang, Rong; Gu, Benxi; Du, Youwei; Zheng, Youdou

    2005-07-11

    Well-faceted ZnO fibers with periodic junction-prisms were synthesized using conventional chemical vapor deposition. The characterization of the fibers by optical and fluorescence microscopy showed that the outer facets of the crystalline fibers provide excellent mirror-like surfaces for guiding light propagation along the fiber stem as well as the periodic junction-prisms. The structure-related optical properties can be fully explained by a microstructural model. The proposed model explains as the decrease in luminance at the junction-prisms is caused by refraction and total or partial reflection of light. The model also explains the luminance enhancement at the junction-prisms is related to waveguiding of the green emission of the ZnO fibers. Further integration of the ZnO junction-prisms into microdevices should provide the microscale modulation for light with different wavelengths, and could be potentially used for enhanced light-illumination arrays.

  7. SQ109, a new drug lead for Chagas disease.

    PubMed

    Veiga-Santos, Phercyles; Li, Kai; Lameira, Lilianne; de Carvalho, Tecia Maria Ulisses; Huang, Guozhong; Galizzi, Melina; Shang, Na; Li, Qian; Gonzalez-Pacanowska, Dolores; Hernandez-Rodriguez, Vanessa; Benaim, Gustavo; Guo, Rey-Ting; Urbina, Julio A; Docampo, Roberto; de Souza, Wanderley; Oldfield, Eric

    2015-04-01

    We tested the antituberculosis drug SQ109, which is currently in advanced clinical trials for the treatment of drug-susceptible and drug-resistant tuberculosis, for its in vitro activity against the trypanosomatid parasite Trypanosoma cruzi, the causative agent of Chagas disease. SQ109 was found to be a potent inhibitor of the trypomastigote form of the parasite, with a 50% inhibitory concentration (IC50) for cell killing of 50 ± 8 nM, but it had little effect (50% effective concentration [EC50], ∼80 μM) in a red blood cell hemolysis assay. It also inhibited extracellular epimastigotes (IC50, 4.6 ± 1 μM) and the clinically relevant intracellular amastigotes (IC50, ∼0.5 to 1 μM), with a selectivity index of ∼10 to 20. SQ109 caused major ultrastructural changes in all three life cycle forms, as observed by light microscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). It rapidly collapsed the inner mitochondrial membrane potential (Δψm) in succinate-energized mitochondria, acting in the same manner as the uncoupler FCCP [carbonyl cyanide 4-(trifluoromethoxy)phenylhydrazone], and it caused the alkalinization of internal acidic compartments, effects that are likely to make major contributions to its mechanism of action. The compound also had activity against squalene synthase, binding to its active site; it inhibited sterol side-chain reduction and, in the amastigote assay, acted synergistically with the antifungal drug posaconazole, with a fractional inhibitory concentration index (FICI) of 0.48, but these effects are unlikely to account for the rapid effects seen on cell morphology and cell killing. SQ109 thus most likely acts, at least in part, by collapsing Δψ/ΔpH, one of the major mechanisms demonstrated previously for its action against Mycobacterium tuberculosis. Overall, the results suggest that SQ109, which is currently in advanced clinical trials for the treatment of drug-susceptible and drug

  8. SQ109, a New Drug Lead for Chagas Disease

    PubMed Central

    Veiga-Santos, Phercyles; Li, Kai; Lameira, Lilianne; de Carvalho, Tecia Maria Ulisses; Huang, Guozhong; Galizzi, Melina; Shang, Na; Li, Qian; Gonzalez-Pacanowska, Dolores; Hernandez-Rodriguez, Vanessa; Benaim, Gustavo; Guo, Rey-Ting; Urbina, Julio A.; Docampo, Roberto; de Souza, Wanderley

    2015-01-01

    We tested the antituberculosis drug SQ109, which is currently in advanced clinical trials for the treatment of drug-susceptible and drug-resistant tuberculosis, for its in vitro activity against the trypanosomatid parasite Trypanosoma cruzi, the causative agent of Chagas disease. SQ109 was found to be a potent inhibitor of the trypomastigote form of the parasite, with a 50% inhibitory concentration (IC50) for cell killing of 50 ± 8 nM, but it had little effect (50% effective concentration [EC50], ∼80 μM) in a red blood cell hemolysis assay. It also inhibited extracellular epimastigotes (IC50, 4.6 ± 1 μM) and the clinically relevant intracellular amastigotes (IC50, ∼0.5 to 1 μM), with a selectivity index of ∼10 to 20. SQ109 caused major ultrastructural changes in all three life cycle forms, as observed by light microscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). It rapidly collapsed the inner mitochondrial membrane potential (Δψm) in succinate-energized mitochondria, acting in the same manner as the uncoupler FCCP [carbonyl cyanide 4-(trifluoromethoxy)phenylhydrazone], and it caused the alkalinization of internal acidic compartments, effects that are likely to make major contributions to its mechanism of action. The compound also had activity against squalene synthase, binding to its active site; it inhibited sterol side-chain reduction and, in the amastigote assay, acted synergistically with the antifungal drug posaconazole, with a fractional inhibitory concentration index (FICI) of 0.48, but these effects are unlikely to account for the rapid effects seen on cell morphology and cell killing. SQ109 thus most likely acts, at least in part, by collapsing Δψ/ΔpH, one of the major mechanisms demonstrated previously for its action against Mycobacterium tuberculosis. Overall, the results suggest that SQ109, which is currently in advanced clinical trials for the treatment of drug-susceptible and drug

  9. Population Pharmacokinetics of Benznidazole in Adult Patients with Chagas Disease

    PubMed Central

    Aldasoro, E.; Guerrero, L.; Posada, E.; Serret, N.; Mejía, T.; Urbina, J. A.; Gascón, J.

    2015-01-01

    The aim of the present study was to build a population pharmacokinetic (popPK) model to characterize benznidazole (BNZ) pharmacokinetics in adults with chronic Chagas disease. This study was a prospective, open-label, single-center clinical trial approved by the local ethics committee. Patients received BNZ at 2.5 mg/kg of body weight/12 h (Abarax, Elea Laboratory, Argentina) for 60 days. Plasma BNZ samples were taken several times during the study and analyzed by high-performance liquid chromatography with UV-visible detection (HPLC-UV). The popPK analysis was done with NONMEMv.7.3. Demographic and biological data were tested as covariates. Intraindividual, interoccasion, and residual variabilities were modeled. Internal and external validations were completed to assess the robustness of the model. Later on, simulations were performed to generate BNZ concentration-time course profiles for different dosage regimens. A total of 358 plasma BNZ concentrations from 39 patients were included in the analysis. A one-compartment PK model characterized by clearance (CL/F) and the apparent volume of distribution (V/F), with first-order absorption (Ka) and elimination, adequately described the data (CL/F, 1.73 liters/h; V/F, 89.6 liters; and Ka, 1.15 h−1). No covariates were found to be significant for CL/F and V/F. Internal and external validations of the final model showed adequate results. Data from simulations revealed that a dose of 2.5 mg/kg/12 h might lead to overexposure in most patients. A lower dose (2.5 mg/kg/24 h) was able to achieve trough BNZ plasma concentrations within the accepted therapeutic range of 3 to 6 mg/liter. In summary, we developed a population PK model for BNZ in adults with chronic Chagas disease. Dosing simulations showed that a BNZ dose of 2.5 mg/kg/24 h will adequately keep BNZ trough plasma concentrations within the recommended target range for the majority of patients. (This study has been registered at EudraCT under number 2011

  10. Foreword: contributions of Arctic PRISM to monitoring western hemispheric shorebirds

    USGS Publications Warehouse

    Skagen, Susan K.; Smith, Paul A.; Andres, Brad A.; Donaldson, Garry; Brown, Stephen

    2012-01-01

    listing under the U.S. Endangered Species Act and the Canadian Species at Risk Act. To meet the need for information on population size and trends, shorebird biologists from Canada and the United States proposed a shared blueprint for shorebird monitoring across the Western Hemisphere in the late 1990s; this effort was undertaken in concert with the development of the Canadian and the U.S. Shorebird Conservation Plans. Soon thereafter, partners in the monitoring effort adopted the name "Program for Regional and International Shorebird Monitoring" (PRISM). Among the primary objectives of PRISM were to estimate the population sizes and trends of breeding North American shorebirds and describe their distributions. PRISM members evaluated ongoing and potential monitoring approached to address 74 taxa (including subspecies) and proposed a combination of arctic and boreal breeding surveys, temperate breeding and non-breeding surveys, and neotropical surveys.

  11. Contributions of Arctic PRISM to monitoring western hemispheric shorebirds

    USGS Publications Warehouse

    Skagen, Susan K.; Smith, Paul A.; Andres, Brad A.; Donaldson, Garry; Brown, Stephen

    2012-01-01

    for assessing its vulnerability and subsequent listing under the U.S. Endangered Species Act and the Canadian Species at Risk Act. To meet the need for information on population size and trends, shorebird biologists from Canada and the United States proposed a shared blueprint for shorebird monitoring across the Western Hemisphere in the late 1990s; this effort was undertaken in concert with the development of the Canadian and U.S. Shorebird Conservation Plans (Donaldson et al. 2000, Brown et aL 2001). Soon thereafter, partners in the monitoring effort adopted the name "Program for Regional and International Shorebird Monitoring" (PRISM). Among the primary objectives of PRISM were to estimate the population sizes and trends of breeding North American shorebirds and describe their distributions (Bart et al. 2002). PRISM members evaluated ongoing and potential monitoring approaches to address 74 taxa (including subspecies) and proposed a combination of arctic andboreal breeding surveys, temperate breeding and non-breeding surveys, and neotropical surveys.

  12. [Study of the factors determining an unexpected occurrecne of Chagas cardiomyopathy in Sucre, Bolivia].

    PubMed

    De Muynck, A; Muñoz, R; Manirankunda, L; Pizzaro, J C; Gutierrez, J

    1998-01-01

    The purpose of this case-control study carried out between February 1, 1994 and December 22, 1994 at the "Instituto de Gastroenterologia Boliviano-Japonés" in Sucre, Bolivia was to determine risk factors for chronic Chagas cardiomyopathy in adult patients with positive serological tests for Trypanosoma cruzi. A total of 196 subjects were included. Inclusion criteria were positive serological tests for Trypanosoma cruzi, residence in the city of Sucre, Bolivia for at least 3 months, and age over 14 years. There were 62 cases presenting electrocardiographic findings consistent with Chagas cardiomyopathy and 134 controls presenting normal electrocardiographic findings. Both cases and controls underwent a standardized protocol including physical examination and laboratory tests. Interviews were set up to evaluate personal and familial history of Chagas disease, socioeconomic status, and presence of Triatoma infestans in the home. Bivariate analysis of data indicated that Chagas cardiomyopathy was associated with the following risk factors: heart rate (p < 0.05), fecaloma (p < 0.05), occupation requiring strenuous physical exertion (p < 0.001), proximity with domestic animals (p < 0.005), especially pigs (p < 0.005), dwelling features including outbuildings, more than 2 bedrooms, and inside ceilings (p < 0.001). Multivariate analysis revealed the following risk factors: occupation requiring strenuous physical exertion (p < 0.005), a yard around the house (p < 0.05), and inside ceilings (p < 0.05). The results of this study show that prevention of chronic Chagas cardiomyopathy in Sucre, Bolivia will depend on improvement of living conditions.

  13. Controlled but not cured: Structural processes and explanatory models of Chagas disease in tropical Bolivia.

    PubMed

    Forsyth, Colin

    2015-11-01

    Dressler (2001:456) characterizes medical anthropology as divided between two poles: the constructivist, which focuses on the "meaning and significance that events have for people," and the structuralist, which emphasizes socioeconomic processes and relationships. This study synthesizes structuralist and constructivist perspectives by investigating how structural processes impact explanatory models of Chagas disease in a highly endemic area. The research took place from March-June 2013 through the Centro Medico Humberto Parra, a non-profit clinic servicing low income populations in Palacios, Bolivia and surrounding communities. Semistructured interviews (n = 68) and consensus analysis questionnaires (n = 48) were administered to people dealing with Chagas disease. In the interview narratives, respondents link Chagas disease with experiences of marginalization and rural poverty, and describe multilayered impediments to accessing treatment. They often view the disease as incurable, but this reflects inconsistent messages from the biomedical system. The consensus analysis results show strong agreement on knowledge of the vector, ethnomedical treatment, and structural factors related to Chagas disease. In interpreting Chagas disease, respondents account for the structural factors which place them at risk and impede access to care. PMID:26432176

  14. Translational challenges of animal models in Chagas disease drug development: a review

    PubMed Central

    Chatelain, Eric; Konar, Nandini

    2015-01-01

    Chagas disease, or American trypanosomiasis, caused by Trypanosoma cruzi parasite infection is endemic in Latin America and presents an increasing clinical challenge due to migrating populations. Despite being first identified over a century ago, only two drugs are available for its treatment, and recent outcomes from the first clinical trials in 40 years were lackluster. There is a critical need to develop new drugs to treat Chagas disease. This requires a better understanding of the progression of parasite infection, and standardization of animal models designed for Chagas disease drug discovery. Such measures would improve comparison of generated data and the predictability of test hypotheses and models designed for translation to human disease. Existing animal models address both disease pathology and treatment efficacy. Available models have limited predictive value for the preclinical evaluation of novel therapies and need to more confidently predict the efficacy of new drug candidates in clinical trials. This review highlights the overall lack of standardized methodology and assessment tools, which has hampered the development of efficacious compounds to treat Chagas disease. We provide an overview of animal models for Chagas disease, and propose steps that could be undertaken to reduce variability and improve predictability of drug candidate efficacy. New technological developments and tools may contribute to a much needed boost in the drug discovery process. PMID:26316715

  15. Immunosuppression and Chagas disease; experience from a non-endemic country.

    PubMed

    Salvador, F; Sánchez-Montalvá, A; Valerio, L; Serre, N; Roure, S; Treviño, B; Pou, D; Sulleiro, E; Bocanegra, C; Molina, I

    2015-09-01

    Reactivation of Chagas disease in the chronic phase may occur when immunosuppression is established, sometimes resulting in high parasitaemia and severe clinical manifestations such as meningitis and meningoencephalitis. Although this situation is being increasingly described, there is still scarce information. This retrospective observational study was performed in three Tropical Medicine Units of Barcelona (Spain) included in the International Health Programme of the Catalan Health Institute (PROSICS). The objective of the study was to describe epidemiological, clinical, microbiological, prognostic and therapeutic data from patients with Chagas disease and any kind of immunosuppressive condition attended in these three institutions from January 2007 to October 2014. From 1823 patients with Chagas disease attending these three centres during the study period, 38 (2%) had some kind of immunosuppressive condition: 12 patients had human immunodeficiency virus infection, 8 patients had neoplasia, 4 patients underwent organ transplantation and 14 patients had an autoimmune disease. Eight (21.1%) patients had cardiac involvement, and six (15.8%) patients had gastrointestinal involvement. Acute Trypanosoma cruzi infection was detected in two Spanish patients. Thirty-one (81.6%) patients received treatment with benznidazole, of whom 17 (54.8%) had some kind of adverse event. No patient had a severe manifestation or reactivation of Chagas disease. Patients with Chagas disease under immunosuppressive conditions are being increasingly described, especially in non-endemic countries. More information about this topic is required and international consensus in the diagnosis, treatment and follow up of these patients must be established to reduce the morbidity and mortality.

  16. Trypanosoma cruzi burden, genotypes, and clinical evaluation of Chilean patients with chronic Chagas cardiopathy.

    PubMed

    Apt, Werner; Arribada, Arturo; Zulantay, Inés; Saavedra, Miguel; Araya, Eduardo; Solari, Aldo; Ortiz, Sylvia; Arriagada, Katherine; Rodríguez, Jorge

    2015-08-01

    There are currently no biomarkers to assess which patients with chronic indeterminate Chagas disease will develop heart disease and which will spend their entire life in this state. We hypothetize that the parasite burden and Trypanosoma cruzi genotypes are related to the presence of heart disease in patients with Chagas disease. This study is aimed to investigate the parasite burden and T. cruzi genotypes in chagasic cardiopaths versus chagasic individuals without cardiac involvement according to the New York Heart Association. Patients with chronic Chagas disease, 50 with and 50 without cardiopathy (controls), groups A and B, respectively, were submitted to anamnesis, physical examination, and electrocardiogram. Echo-Doppler was performed for group A; all important known causes of cardiopathy were discarded. Xenodiagnosis, conventional PCR, and quantitative PCR were performed on patients of both groups. T. cruzi genotyping was done for 25 patients of group A and 20 of group B. The 50 cardiopaths had 80 electrocardiographic alterations, most of them in grade II of the New York Heart Association classification; 49 were classified in grade I by Echo-Doppler, and only one patient was in grade III. The difference in average parasitemia in patients of groups A and B was not significant. The most frequent T. cruzi DTU found was TcV. The parasite burden and genotype of the groups with and without cardiopathy were similar. Graphical abstract Imagen 1 Chronic chagas cardiopathy chest X-ray heart enlargement Figure 2 Chronic Chagas cardiopathy microaneurism of left ventricle. Cineangiography.

  17. Controlled but not cured: Structural processes and explanatory models of Chagas disease in tropical Bolivia.

    PubMed

    Forsyth, Colin

    2015-11-01

    Dressler (2001:456) characterizes medical anthropology as divided between two poles: the constructivist, which focuses on the "meaning and significance that events have for people," and the structuralist, which emphasizes socioeconomic processes and relationships. This study synthesizes structuralist and constructivist perspectives by investigating how structural processes impact explanatory models of Chagas disease in a highly endemic area. The research took place from March-June 2013 through the Centro Medico Humberto Parra, a non-profit clinic servicing low income populations in Palacios, Bolivia and surrounding communities. Semistructured interviews (n = 68) and consensus analysis questionnaires (n = 48) were administered to people dealing with Chagas disease. In the interview narratives, respondents link Chagas disease with experiences of marginalization and rural poverty, and describe multilayered impediments to accessing treatment. They often view the disease as incurable, but this reflects inconsistent messages from the biomedical system. The consensus analysis results show strong agreement on knowledge of the vector, ethnomedical treatment, and structural factors related to Chagas disease. In interpreting Chagas disease, respondents account for the structural factors which place them at risk and impede access to care.

  18. [Postpartum treatment without interrupting breastfeeding in a patient with Chagas disease].

    PubMed

    Vela-Bahena, Luz Elena; Vergara, Raymundo; Vite, Ludmila; Ramos, Celso

    2015-08-01

    Chagas disease is a problem of global public health. It is caused by the protozoan Trypanosoma cruzi, which is acquired through exposure to infected triatomine feces, blood transfusion, organ transplantation, orally, by laboratory accidents and congenitally (mother-child); the latter is a public health problem in endemic countries and is the most common form in non-endemic countries. In Mexico, there are few studies on congenital transmission of Chagas disease. The majority of pregnant women with Chagas disease are chronic and asymptomatic, and there is a risk of products with low birth weight and abortions, yet most infants are asymptomatic and treatment in pregnancy is contraindicated. Here, we report a case of a 24-year-old who was diagnosed with Chagas disease by donating blood and confirmed by the State Laboratory of Public Health. Before starting treatment, 13 weeks pregnancy was detected and followed up until the birth; mother was seropositive for Chagas disease and child was negative by parasitological studies. Breastfeeding was initiated at birth and one month, after consulting with experts, treating the mother began with benznidazole for 45 days; in general, the treatment was well tolerated, but the patient remained seropositive. PMID:26591033

  19. Progress towards the elimination of transmission of Chagas disease in Latin America.

    PubMed

    Moncayo, A

    1997-01-01

    From a global perspective, Chagas disease represents the third largest tropical disease burden after malaria and schistosomiasis. The estimated average annual per-capita gross domestic product in Latin America is US$2,966. The economic loss for the continent due to early mortality and disability by this disease in economically most productive young adults currently amounts to US$8,156 million which is equivalent to 2.5% of the external debt of the whole continent in 1995. In 1991, the Ministers of Health of Argentina, Bolivia, Brazil, Chile, Paraguay and Uruguay, launched the Southern Cone Initiative for elimination of transmission of Chagas disease. The progress towards elimination of vectorial and transfusional transmission of Chagas disease in Uruguay, Chile, Argentina and Brazil has been documented by reports from the national control programmes of the above countries. Current data on disinfestation of houses, coverage of screening in blood banks and serology in children and young adults indicate that the interruption of the vectorial and transfusional transmission of Chagas disease will be achieved in these countries as follows: Uruguay and Chile in 1999, Brazil and Argentina in 2003. By eliminating the transmission of Chagas disease in the above countries, the incidence of the disease in the whole of Latin America will be reduced by more than 70%. PMID:9477549

  20. Pupillary Light Reflexes are Associated with Autonomic Dysfunction in Bolivian Diabetics But Not Chagas Disease Patients.

    PubMed

    Halperin, Anthony; Pajuelo, Monica; Tornheim, Jeffrey A; Vu, Nancy; Carnero, Andrés M; Galdos-Cardenas, Gerson; Ferrufino, Lisbeth; Camacho, Marilyn; Justiniano, Juan; Colanzi, Rony; Bowman, Natalie M; Morris, Tiffany; MacDougall, Hamish; Bern, Caryn; Moore, Steven T; Gilman, Robert H

    2016-06-01

    Autonomic dysfunction is common in Chagas disease and diabetes. Patients with either condition complicated by cardiac autonomic dysfunction face increased mortality, but no clinical predictors of autonomic dysfunction exist. Pupillary light reflexes (PLRs) may identify such patients early, allowing for intensified treatment. To evaluate the significance of PLRs, adults were recruited from the outpatient endocrine, cardiology, and surgical clinics at a Bolivian teaching hospital. After testing for Chagas disease and diabetes, participants completed conventional autonomic testing (CAT) evaluating their cardiovascular responses to Valsalva, deep breathing, and orthostatic changes. PLRs were measured using specially designed goggles, then CAT and PLRs were compared as measures of autonomic dysfunction. This study analyzed 163 adults, including 96 with Chagas disease, 35 patients with diabetes, and 32 controls. PLRs were not significantly different between Chagas disease patients and controls. Patients with diabetes had longer latency to onset of pupil constriction, slower maximum constriction velocities, and smaller orthostatic ratios than nonpatients with diabetes. PLRs correlated poorly with CAT results. A PLR-based clinical risk score demonstrated a 2.27-fold increased likelihood of diabetes complicated by autonomic dysfunction compared with the combination of blood tests, CAT, and PLRs (sensitivity 87.9%, specificity 61.3%). PLRs represent a promising tool for evaluating subclinical neuropathy in patients with diabetes without symptomatic autonomic dysfunction. Pupillometry does not have a role in the evaluation of Chagas disease patients. PMID:27044564

  1. Pupillary Light Reflexes are Associated with Autonomic Dysfunction in Bolivian Diabetics But Not Chagas Disease Patients.

    PubMed

    Halperin, Anthony; Pajuelo, Monica; Tornheim, Jeffrey A; Vu, Nancy; Carnero, Andrés M; Galdos-Cardenas, Gerson; Ferrufino, Lisbeth; Camacho, Marilyn; Justiniano, Juan; Colanzi, Rony; Bowman, Natalie M; Morris, Tiffany; MacDougall, Hamish; Bern, Caryn; Moore, Steven T; Gilman, Robert H

    2016-06-01

    Autonomic dysfunction is common in Chagas disease and diabetes. Patients with either condition complicated by cardiac autonomic dysfunction face increased mortality, but no clinical predictors of autonomic dysfunction exist. Pupillary light reflexes (PLRs) may identify such patients early, allowing for intensified treatment. To evaluate the significance of PLRs, adults were recruited from the outpatient endocrine, cardiology, and surgical clinics at a Bolivian teaching hospital. After testing for Chagas disease and diabetes, participants completed conventional autonomic testing (CAT) evaluating their cardiovascular responses to Valsalva, deep breathing, and orthostatic changes. PLRs were measured using specially designed goggles, then CAT and PLRs were compared as measures of autonomic dysfunction. This study analyzed 163 adults, including 96 with Chagas disease, 35 patients with diabetes, and 32 controls. PLRs were not significantly different between Chagas disease patients and controls. Patients with diabetes had longer latency to onset of pupil constriction, slower maximum constriction velocities, and smaller orthostatic ratios than nonpatients with diabetes. PLRs correlated poorly with CAT results. A PLR-based clinical risk score demonstrated a 2.27-fold increased likelihood of diabetes complicated by autonomic dysfunction compared with the combination of blood tests, CAT, and PLRs (sensitivity 87.9%, specificity 61.3%). PLRs represent a promising tool for evaluating subclinical neuropathy in patients with diabetes without symptomatic autonomic dysfunction. Pupillometry does not have a role in the evaluation of Chagas disease patients.

  2. Socio-Cultural Aspects of Chagas Disease: A Systematic Review of Qualitative Research

    PubMed Central

    Ventura-Garcia, Laia; Roura, Maria; Pell, Christopher; Posada, Elisabeth; Gascón, Joaquim; Aldasoro, Edelweis; Muñoz, Jose; Pool, Robert

    2013-01-01

    Background Globally, more than 10 million people are infected with Trypanosoma cruzi, which causes about 20 000 annual deaths. Although Chagas disease is endemic to certain regions of Latin America, migratory flows have enabled its expansion into areas where it was previously unknown. Economic, social and cultural factors play a significant role in its presence and perpetuation. This systematic review aims to provide a comprehensive overview of qualitative research on Chagas disease, both in endemic and non-endemic countries. Methodology/Principal Findings Searches were carried out in ten databases, and the bibliographies of retrieved studies were examined. Data from thirty-three identified studies were extracted, and findings were analyzed and synthesized along key themes. Themes identified for endemic countries included: socio-structural determinants of Chagas disease; health practices; biomedical conceptions of Chagas disease; patient's experience; and institutional strategies adopted. Concerning non-endemic countries, identified issues related to access to health services and health seeking. Conclusions The emergence and perpetuation of Chagas disease depends largely on socio-cultural aspects influencing health. As most interventions do not address the clinical, environmental, social and cultural aspects jointly, an explicitly multidimensional approach, incorporating the experiences of those affected is a potential tool for the development of long-term successful programs. Further research is needed to evaluate this approach. PMID:24069473

  3. Translational challenges of animal models in Chagas disease drug development: a review.

    PubMed

    Chatelain, Eric; Konar, Nandini

    2015-01-01

    Chagas disease, or American trypanosomiasis, caused by Trypanosoma cruzi parasite infection is endemic in Latin America and presents an increasing clinical challenge due to migrating populations. Despite being first identified over a century ago, only two drugs are available for its treatment, and recent outcomes from the first clinical trials in 40 years were lackluster. There is a critical need to develop new drugs to treat Chagas disease. This requires a better understanding of the progression of parasite infection, and standardization of animal models designed for Chagas disease drug discovery. Such measures would improve comparison of generated data and the predictability of test hypotheses and models designed for translation to human disease. Existing animal models address both disease pathology and treatment efficacy. Available models have limited predictive value for the preclinical evaluation of novel therapies and need to more confidently predict the efficacy of new drug candidates in clinical trials. This review highlights the overall lack of standardized methodology and assessment tools, which has hampered the development of efficacious compounds to treat Chagas disease. We provide an overview of animal models for Chagas disease, and propose steps that could be undertaken to reduce variability and improve predictability of drug candidate efficacy. New technological developments and tools may contribute to a much needed boost in the drug discovery process.

  4. Triatominae Biochemistry Goes to School: Evaluation of a Novel Tool for Teaching Basic Biochemical Concepts of Chagas Disease Vectors

    ERIC Educational Resources Information Center

    Cunha, Leonardo Rodrigues; de Oliveria Cudischevitch, Cecília; Carneiro, Alan Brito; Macedo, Gustavo Bartholomeu; Lannes, Denise; da Silva-Neto, Mário Alberto Cardoso

    2014-01-01

    We evaluate a new approach to teaching the basic biochemistry mechanisms that regulate the biology of Triatominae, major vectors of "Trypanosoma cruzi," the causative agent of Chagas disease. We have designed and used a comic book, "Carlos Chagas: 100 years after a hero's discovery" containing scientific information…

  5. Triple Wollaston-prism complete-Stokes imaging polarimeter.

    PubMed

    Perreault, John D

    2013-10-01

    Imaging polarimetry is emerging as a powerful tool for remote sensing in space science, Earth science, biology, defense, national security, and industry. Polarimetry provides complementary information about a scene in the visible and infrared wavelengths. For example, surface texture, material composition, and molecular structure will affect the polarization state of reflected, scattered, or emitted light. We demonstrate an imaging polarimeter design that uses three Wollaston prisms, addressing several technical challenges associated with moving remote-sensing platforms. This compact design has no moving polarization elements and separates the polarization components in the pupil (or Fourier) plane, analogous to the way a grating spectrometer works. In addition, this concept enables simultaneous characterization of unpolarized, linear, and circular components of optical polarization. The results from a visible-wavelength prototype of this imaging polarimeter are presented, demonstrating remote sensitivity to material properties. This work enables new remote sensing capabilities and provides a viable design concept for extensions into infrared wavelengths. PMID:24081075

  6. The PRISM project: Infrastructure and algorithms for parallel eigensolvers

    SciTech Connect

    Bischof, C.; Sun, X.; Huss-Lederman, S.; Tsao, A.

    1993-12-31

    The goal of the PRISM project is the development of infrastructure and algorithms for the parallel solution of eigenvalue problems. We are currently investigating a complete eigensolver based on the Invariant Subspace Decomposition Algorithm for dense symmetric matrices (SYISDA). After briefly reviewing the SYISDA approach, we discuss the algorithmic highlights of a distributed-memory implementation of an eigensolver based on this approach. These include a fast matrix-matrix multiplication algorithm, a new approach to parallel band reduction and tridiagonalization, and a harness for coordinating the divide-and-conquer parallelism in the problem. We also present performance results of these kernels as well as the overall SYISDA implementation on the Intel Touchstone Delta prototype and the IBM SP/1.

  7. Hybrid-integrated prism array optoelectronic targeting system

    NASA Astrophysics Data System (ADS)

    Chang, C. C.; Chang, H. C.; Tang, L. C.; Young, W. K.; Wang, J. C.; Huang, K. L.

    2005-11-01

    This investigation proposes a cost-effective, compact, and robust optoelectronic targeting system for measuring ballistic impact velocity and the distribution of projectile motion. The major elements of this system are four photo-gates hybridized by compound one-dimensional prism array and analog/digital electronic components. The number of light sources and photodetectors used in a photo-gate was reduced to one pair of light source and photodetector. The average velocity and location of the projectile are determined according to the measured time intervals ( ˜10 -8 s) passing each pair. The system can accurately measure the velocity of a bullet as it leaves a gun barrel, as well as the velocity at specific points along the trajectory outside the firearm. Additionally, the system uses a widespread low-powered laser pointer as a light source. Compared with other optoelectronic targeting systems that use high-powered lasers, the proposed system is both economical and safe.

  8. Dove prism based rotating dual beam bidirectional Doppler OCT.

    PubMed

    Blatter, Cedric; Coquoz, Séverine; Grajciar, Branislav; Singh, Amardeep S G; Bonesi, Marco; Werkmeister, René M; Schmetterer, Leopold; Leitgeb, Rainer A

    2013-07-01

    Traditional Doppler OCT is highly sensitive to motion artifacts due to the dependence on the Doppler angle. This limits its accuracy in clinical practice. To overcome this limitation, we use a bidirectional dual beam technique equipped with a novel rotating scanning scheme employing a Dove prism. The volume is probed from two distinct illumination directions with variable controlled incidence plane, allowing for reconstruction of the true flow velocity at arbitrary vessel orientations. The principle is implemented with Swept Source OCT at 1060nm with 100,000 A-Scans/s. We apply the system to resolve pulsatile retinal absolute blood velocity by performing segment scans around the optic nerve head and circumpapillary scan time series.

  9. Optical device with conical input and output prism faces

    DOEpatents

    Brunsden, Barry S.

    1981-01-01

    A device for radially translating radiation in which a right circular cylinder is provided at each end thereof with conical prism faces. The faces are oppositely extending and the device may be severed in the middle and separated to allow access to the central part of the beam. Radiation entering the input end of the device is radially translated such that radiation entering the input end at the perimeter is concentrated toward the output central axis and radiation at the input central axis is dispersed toward the output perimeter. Devices are disclosed for compressing beam energy to enhance drilling techniques, for beam manipulation of optical spatial frequencies in the Fourier plane and for simplification of dark field and color contrast microscopy. Both refracting and reflecting devices are disclosed.

  10. Larmor labeling of neutron spin using superconducting Wollaston prisms

    NASA Astrophysics Data System (ADS)

    Li, Fankang

    Neutron spin Larmor labeling using magnetic Wollaston prisms (WP) provides a way to overcome some of the limitations arising from the nature of neutron beams: low flux and divergence. Using superconducting films and tapes, a series of strong, well-defined shaped magnetic fields can be produced due to both the zero-resistance and Meissner effect in superconductors. Using finite element simulations, the criterion to build a superconducting magnetic Wollaston prism with high encoding efficiency and low Larmor phase aberrations are presented. To achieve a high magnetic field and simplify the maintenance, we optimize the design using careful thermal analysis. The measured neutron spin flipping efficiency is measured to be independent of both the neutron wavelength and energizing current, which is a significant improvement over other devices with similar functions. A highly linear variation of the Larmor phase is measured across the device, which ensures a highly uniform encoding of scattering angles into the neutron spin Larmor phase. Using two WPs, the correlation function for a colloidal silica sample was measured by spin echo modulated small angle neutron scattering (SEMSANS) and agrees well with other techniques. Using Monte Carlo code (McStas), we further investigated the SEMSANS setup and showed the requirements to improve its performance. We have proposed a new technique to implement neutron spin echo on a triple axis neutron spectrometer to achieve high resolution measurements of the lifetime of dispersive phonon excitations. The spin echo is tuned by appropriate choice of magnetic fields instead of physically tilting the coils used in traditional methods. This new approach allows a higher energy resolution and a larger effective tilting angle and hence larger group velocity to be measured.

  11. Circulating serum markers and QRS scar score in Chagas cardiomyopathy.

    PubMed

    Clark, Eva H; Marks, Morgan A; Gilman, Robert H; Fernandez, Antonio B; Crawford, Thomas C; Samuels, Aaron M; Hidron, Alicia I; Galdos-Cardenas, Gerson; Menacho-Mendez, Gilberto Silvio; Bozo-Gutierrez, Ricardo W; Martin, Diana L; Bern, Caryn

    2015-01-01

    Approximately 8 million people have Trypanosoma cruzi infection, and nearly 30% will manifest Chagas cardiomyopathy (CC). Identification of reliable early indicators of CC risk would enable prioritization of treatment to those with the highest probability of future disease. Serum markers and electrocardiogram (EKG) changes were measured in 68 T. cruzi-infected individuals in various stages of cardiac disease and 17 individuals without T. cruzi infection or cardiac disease. T. cruzi-infected individuals were assigned to stage A (normal EKG/chest x-ray [CXR]), B (abnormal EKG/normal CXR), or C (abnormal EKG/cardiac structural changes). Ten serum markers were measured using enzyme-linked immunosorbent assay (ELISA)/Luminex, and QRS scores were calculated. Higher concentrations of transforming growth factor-β1 (TGFβ1), and TGFβ2 were associated with stage B compared with stage A. Matrix Metalloproteinase 2 (MMP2), Tissue Inhibitors of MMP 1, QRS score, and Brain Natriuretic Protein rose progressively with increasing CC severity. Elevated levels of several markers of cardiac damage and inflammation are seen in early CC and warrant additional evaluation in longitudinal studies.

  12. Circulating Serum Markers and QRS Scar Score in Chagas Cardiomyopathy

    PubMed Central

    Clark, Eva H.; Marks, Morgan A.; Gilman, Robert H.; Fernandez, Antonio B.; Crawford, Thomas C.; Samuels, Aaron M.; Hidron, Alicia I.; Galdos-Cardenas, Gerson; Menacho-Mendez, Gilberto Silvio; Bozo-Gutierrez, Ricardo W.; Martin, Diana L.; Bern, Caryn

    2015-01-01

    Approximately 8 million people have Trypanosoma cruzi infection, and nearly 30% will manifest Chagas cardiomyopathy (CC). Identification of reliable early indicators of CC risk would enable prioritization of treatment to those with the highest probability of future disease. Serum markers and electrocardiogram (EKG) changes were measured in 68 T. cruzi-infected individuals in various stages of cardiac disease and 17 individuals without T. cruzi infection or cardiac disease. T. cruzi-infected individuals were assigned to stage A (normal EKG/chest x-ray [CXR]), B (abnormal EKG/normal CXR), or C (abnormal EKG/cardiac structural changes). Ten serum markers were measured using enzyme-linked immunosorbent assay (ELISA)/Luminex, and QRS scores were calculated. Higher concentrations of transforming growth factor-β1 (TGFβ1), and TGFβ2 were associated with stage B compared with stage A. Matrix Metalloproteinase 2 (MMP2), Tissue Inhibitors of MMP 1, QRS score, and Brain Natriuretic Protein rose progressively with increasing CC severity. Elevated levels of several markers of cardiac damage and inflammation are seen in early CC and warrant additional evaluation in longitudinal studies. PMID:25385865

  13. Chagas Cardiomyopathy in New Orleans and the Southeastern United States

    PubMed Central

    Hsu, Robert C.; Burak, Joshua; Tiwari, Sumit; Chakraborti, Chayan; Sander, Gary E.

    2016-01-01

    Background: Chagas disease (CD), caused by Trypanosoma cruzi, affects 6-7 million people worldwide annually, primarily in Central and South America, and >300,000 people in the United States. CD consists of acute and chronic stages. Hallmarks of acute CD include fever, myalgia, diaphoresis, hepatosplenomegaly, and myocarditis. Symptoms of chronic CD include pathologic involvement of the heart, esophagus, and colon. Myocardial involvement is identifiable by electrocardiogram and cardiac magnetic resonance imaging showing inflammation and left ventricular wall functional abnormalities. Case Reports: We present two cases of CD identified in a single hospital in the Southeastern United States. Case 1 presents a patient with symptoms of anginal chest pain and associated shortness of breath with myocardial involvement suggestive of ischemic infarction but normal coronary arteries. Case 2 describes a patient with no physical symptoms and echocardiogram with ejection fraction of 50% with posterolateral and anterolateral wall hypokinesis but normal coronary arteries. Conclusion: With a growing number of immigrants from Central and South America in the United States, it is imperative for clinicians to include CD as part of the differential diagnosis for patients presenting with heart disease who have a history of exposure to T. cruzi endemic areas. PMID:27660581

  14. Urbanization, land tenure security and vector-borne Chagas disease.

    PubMed

    Levy, Michael Z; Barbu, Corentin M; Castillo-Neyra, Ricardo; Quispe-Machaca, Victor R; Ancca-Juarez, Jenny; Escalante-Mejia, Patricia; Borrini-Mayori, Katty; Niemierko, Malwina; Mabud, Tarub S; Behrman, Jere R; Naquira-Velarde, Cesar

    2014-08-22

    Modern cities represent one of the fastest growing ecosystems on the planet. Urbanization occurs in stages; each stage characterized by a distinct habitat that may be more or less susceptible to the establishment of disease vector populations and the transmission of vector-borne pathogens. We performed longitudinal entomological and epidemiological surveys in households along a 1900 × 125 m transect of Arequipa, Peru, a major city of nearly one million inhabitants, in which the transmission of Trypanosoma cruzi, the aetiological agent of Chagas disease, by the insect vector Triatoma infestans, is an ongoing problem. The transect spans a cline of urban development from established communities to land invasions. We find that the vector is tracking the development of the city, and the parasite, in turn, is tracking the dispersal of the vector. New urbanizations are free of vector infestation for decades. T. cruzi transmission is very recent and concentrated in more established communities. The increase in land tenure security during the course of urbanization, if not accompanied by reasonable and enforceable zoning codes, initiates an influx of construction materials, people and animals that creates fertile conditions for epidemics of some vector-borne diseases.

  15. Chagas Cardiomyopathy in New Orleans and the Southeastern United States

    PubMed Central

    Hsu, Robert C.; Burak, Joshua; Tiwari, Sumit; Chakraborti, Chayan; Sander, Gary E.

    2016-01-01

    Background: Chagas disease (CD), caused by Trypanosoma cruzi, affects 6-7 million people worldwide annually, primarily in Central and South America, and >300,000 people in the United States. CD consists of acute and chronic stages. Hallmarks of acute CD include fever, myalgia, diaphoresis, hepatosplenomegaly, and myocarditis. Symptoms of chronic CD include pathologic involvement of the heart, esophagus, and colon. Myocardial involvement is identifiable by electrocardiogram and cardiac magnetic resonance imaging showing inflammation and left ventricular wall functional abnormalities. Case Reports: We present two cases of CD identified in a single hospital in the Southeastern United States. Case 1 presents a patient with symptoms of anginal chest pain and associated shortness of breath with myocardial involvement suggestive of ischemic infarction but normal coronary arteries. Case 2 describes a patient with no physical symptoms and echocardiogram with ejection fraction of 50% with posterolateral and anterolateral wall hypokinesis but normal coronary arteries. Conclusion: With a growing number of immigrants from Central and South America in the United States, it is imperative for clinicians to include CD as part of the differential diagnosis for patients presenting with heart disease who have a history of exposure to T. cruzi endemic areas.

  16. Clinical aspects of Chagas disease and implications for novel therapies.

    PubMed

    Menezes, Cristiane; Costa, Germano Carneiro; Gollob, Kenneth J; Dutra, Walderez O

    2011-09-01

    The interaction between the protozoan parasite Trypanosoma cruzi and the human host dates back 9000 years, as demonstrated by molecular analysis of material obtained from Andean mummies indicating the presence of the parasite's kinetoplast DNA in populations from Chile and Peru. This long-established interaction, which persists today, demonstrates that T. cruzi has established a very well adapted relationship with the human host. From a host-parasite relationship point-of-view this is desirable, however, such a high degree of adaptation is perhaps the foundation for many of the unknowns that surround this disease. Unveiling of the immunological mechanisms that underlie the establishment of pathology, identification of parasite-associated factors that determine strain-differential tissue tropism, discovery of host genetic elements that influence the development of different clinical forms of the disease, and understanding environmental factors that may influence the host-parasite interactions, are some of the key questions remaining to be answered. The response to these questions will aid in addressing some of the current challenges in Chagas disease: fulfilling the need for efficient diagnosis, developing effective prophylactic measures, discovering effective therapeutics, and finding methods to control disease progression.

  17. Lack of Segregation between Two Species of Chagas Disease Vectors

    PubMed Central

    Mota, Theo; Lorenzo, Marcelo Gustavo

    2012-01-01

    Triatoma infestans and Panstrongylus megistus are relevant Chagas disease vectors. An apparent segregation among these triatomine species inside human households was suggested to rely on mutual repellence between them. However, P. megistus and T. infestans show aggregation responses to chemical signals emitted by the other species. These findings do not rule out the possibility that stimuli other than chemical signals could mediate repellence when these species exploit shelters simultaneously. In the present study, we investigated how P. megistus and T. infestans exploit shelters in controlled laboratory conditions and how insect density and environmental illumination modulate this behavior. We evaluated whether these species aggregate inside shelters or mutually repel each other. Panstrongylus megistus and T. infestans show specific patterns of shelter exploitation, which are differentially affected by insect density and environment illumination. In particular, P. megistus is more sensitive to insect density than T. infestans, whereas T. infestans shows higher sensitivity to illumination than P. megistus. Nevertheless, these species exploit shelters randomly without any apparent repellence. PMID:22764300

  18. Genomic Changes of Chagas Disease Vector, South America

    PubMed Central

    Dujardin, Jean Pierre; Nicolini, Paula; Caraccio, María Noel; Rose, Virginia; Tellez, Tatiana; Bermúdez, Hernán; Bargues, María Dolores; Mas-Coma, Santiago; O’Connor, José Enrique; Pérez, Ruben

    2004-01-01

    We analyzed the main karyologic changes that have occurred during the dispersion of Triatoma infestans, the main vector of Chagas disease. We identified two allopatric groups, named Andean and non-Andean. The Andean specimens present C-heterochromatic blocks in most of their 22 chromosomes, whereas non-Andean specimens have only 4–7 autosomes with C-banding. These heterochromatin differences are the likely cause of a striking DNA content variation (approximately 30%) between Andean and non-Andean insects. Our study, together with previous historical and genetic data, suggests that T. infestans was originally a sylvatic species, with large quantities of DNA and heterochromatin, inhabiting the Andean region of Bolivia. However, the spread of domestic T. infestans throughout the non-Andean regions only involved insects with an important reduction of heterochromatin and DNA amounts. We propose that heterochromatin and DNA variation mainly reflected adaptive genomic changes that contribute to the ability of T. infestans to survive, reproduce, and disperse in different environments. PMID:15109410

  19. Urbanization, land tenure security and vector-borne Chagas disease

    PubMed Central

    Levy, Michael Z.; Barbu, Corentin M.; Castillo-Neyra, Ricardo; Quispe-Machaca, Victor R.; Ancca-Juarez, Jenny; Escalante-Mejia, Patricia; Borrini-Mayori, Katty; Niemierko, Malwina; Mabud, Tarub S.; Behrman, Jere R.; Naquira-Velarde, Cesar

    2014-01-01

    Modern cities represent one of the fastest growing ecosystems on the planet. Urbanization occurs in stages; each stage characterized by a distinct habitat that may be more or less susceptible to the establishment of disease vector populations and the transmission of vector-borne pathogens. We performed longitudinal entomological and epidemiological surveys in households along a 1900 × 125 m transect of Arequipa, Peru, a major city of nearly one million inhabitants, in which the transmission of Trypanosoma cruzi, the aetiological agent of Chagas disease, by the insect vector Triatoma infestans, is an ongoing problem. The transect spans a cline of urban development from established communities to land invasions. We find that the vector is tracking the development of the city, and the parasite, in turn, is tracking the dispersal of the vector. New urbanizations are free of vector infestation for decades. T. cruzi transmission is very recent and concentrated in more established communities. The increase in land tenure security during the course of urbanization, if not accompanied by reasonable and enforceable zoning codes, initiates an influx of construction materials, people and animals that creates fertile conditions for epidemics of some vector-borne diseases. PMID:24990681

  20. Direct micromethod for diagnosis of acute and congenital Chagas' disease.

    PubMed Central

    Feilij, H; Muller, L; Gonzalez Cappa, S M

    1983-01-01

    A microhematocrit concentration method (MH) for immediate diagnosis of Chagas' disease during the acute stage or in congenital cases was standardized. Parasitemia as low as 1,000 parasites per ml was detected, after centrifugation of six 50-microliters capillary tubes, by 10-min microscopic observation of each buffy coat spread between slide and cover glass. Operator's time was reduced by at least one-third when compared with a fresh blood observation (FB). In 12 of the 15 patients studied, diagnosis was performed in 4.9 +/- 3.08 min with MH, whereas 27.0 +/- 12.1 min were necessary when FB was used. In the three remaining patients whose FB results were negative, MH became positive after 13, 16, and 40 min. In our experience, FB proved to be more sensitive than previously reported. Suckling mouse inoculation also proved to be sensitive but, as in xenodiagnosis and in hemoculture, the delay in getting the final result was a limiting factor. PMID:6413530

  1. Chagas disease (Trypanosoma cruzi) and HIV co-infection in Colombia.

    PubMed

    Hernández, Carolina; Cucunubá, Zulma; Parra, Edgar; Toro, German; Zambrano, Pilar; Ramírez, Juan David

    2014-09-01

    Chagas disease is a complex zoonotic pathology caused by the kinetoplastid Trypanosoma cruzi. This parasite presents remarkable genetic variability and has been grouped into six discrete typing units (DTUs). The association between the DTUs and clinical outcome remains unknown. Chagas disease and co-infection with HIV/AIDS has been reported widely in Brazil and Argentina. Herein, we present the molecular analyses from a Chagas disease patient with HIV/AIDS co-infection in Colombia who presented severe cardiomyopathy, pleural effusion, and central nervous system involvement. A mixed infection by T. cruzi genotypes was detected. We suggest including T. cruzi in the list of opportunistic pathogens for the management of HIV patients in Colombia. The epidemiological implications of this finding are discussed.

  2. [What is not searched, it is difficult to find: Chagas' disease].

    PubMed

    Briceno, Luis; Mosca, Walter

    2016-05-01

    A conservative estimation indicates that more than 400 000 Latin American immigrants are living in Italy. Several studies have shown that among these, the prevalence of Chagas disease is between 3.9% and 17%, so it is not unlikely to find a patient with this disease during a cardiology visit. How many patients from Latin America are diagnosed with heart failure in Italy and no one has ever thought about a possible Chagas disease? This brief review describes the situation of the disease in Italy, its characteristics, the etiology of this disease and its treatment. The latter aspect will be discussed considering the recent published results of the BENEFIT study, where it was found that treatment with benznidazole in patients with Chagas' cardiomyopathy is able to reduce significantly the detection of parasites in the blood, but it is not able to prevent clinical deterioration during 5 years of follow-up. The possible implications of these results will be discussed.

  3. The Sphingolipid Biosynthetic Pathway Is a Potential Target for Chemotherapy against Chagas Disease

    PubMed Central

    Koeller, Carolina Macedo; Heise, Norton

    2011-01-01

    The protozoan parasite Trypanosoma cruzi is the causative agent of human Chagas disease, for which there currently is no cure. The life cycle of T. cruzi is complex, including an extracellular phase in the triatomine insect vector and an obligatory intracellular stage inside the vertebrate host. These phases depend on a variety of surface glycosylphosphatidylinositol-(GPI-) anchored glycoconjugates that are synthesized by the parasite. Therefore, the surface expression of GPI-anchored components and the biosynthetic pathways of GPI anchors are attractive targets for new therapies for Chagas disease. We identified new drug targets for chemotherapy by taking the available genome sequence information and searching for differences in the sphingolipid biosynthetic pathways (SBPs) of mammals and T. cruzi. In this paper, we discuss the major steps of the SBP in mammals, yeast and T. cruzi, focusing on the IPC synthase and ceramide remodeling of T. cruzi as potential therapeutic targets for Chagas disease. PMID:21603271

  4. [José Lima Pedreira de Freitas and the redefinition and control of Chagas disease].

    PubMed

    Rocha, Juan Stuardo Yazlle

    2016-08-01

    A brief overview of the evolution of knowledge about Chagas disease since its discovery by Carlos Chagas in 1909 until the mid-1940s is presented. The trajectory of physician Pedreira de Freitas and his growing involvement in research in the area led to his contributions to laboratory diagnosis - which lent consistency and security to epidemiological surveys of Chagas disease - and the redefinition of the scale of the disease in Brazil and the Americas with its terrible social and economic impact. His proposal for the disease prevention model - based on selective purging in the application of insecticide - was adopted nationally and internationally and made it possible to bring the disease under control in Brazil and other countries. He devoted himself with equal intensity to enhancing the teaching of medical practices in the community and was a pioneer in the implementation of preventive medicine in medical education in Brazil. PMID:27557035

  5. Karyotype and spermatogenesis in Triatoma lenti (Hemiptera: Triatominae), a potential Chagas vector.

    PubMed

    Alevi, K C C; Mendonça, P P; Succi, M; Pereira, N P; Rosa, J A; Azeredo-Oliveira, M T V

    2012-12-17

    All species of Triatominae are susceptible to infection by Trypanosoma cruzi (Kinetoplastida: Trypanosomatidae) and consequently, potential insect vectors of Chagas disease. Currently, there are 140 known species of triatomine bugs, which can be grouped into specific species complexes. The species Triatoma lenti (Hemiptera: Triatominae) is found only in Brazil and is considered a potential vector of Chagas disease. We karyotyped male T. lenti and examined its spermatogenesis in detail. The karyotype was found to be 2n = 20A + XY, demonstrating that this organism has the modal chromosome set found in triatomines. This new information concerning males of this species contributed to biological data that will be useful for understanding this potentially important Chagas disease vector.

  6. Cost-effectiveness of Chagas disease interventions in latin america and the Caribbean: Markov models.

    PubMed

    Wilson, Leslie S; Strosberg, Arthur M; Barrio, Kimberly

    2005-11-01

    Chagas disease is a parasitic disease in Latin America. Despite vector control programs that have reduced incidence by 70%, there are at least 12-14 million prevalent cases. We used a Markov model to examine strategies for control and treatment of Chagas disease that compared annual costs, life expectancies, and cost-effectiveness of three vector control and drug treatment strategies. Vector control programs alone and vector control plus drug treatment are dominant over no vector control (i.e., less costly and save more lives), and vector control plus drug is highly cost-effective compared with vector control alone. We demonstrated expected changes in deaths over time resulting from various prevention approaches. Vector control affects primarily incidence, not decreasing deaths and prevalence for 30 years, while drug treatment affects prevalence and deaths immediately. The best strategy to combat Chagas disease is combinations of vector control and a potential new drug.

  7. [What is not searched, it is difficult to find: Chagas' disease].

    PubMed

    Briceno, Luis; Mosca, Walter

    2016-05-01

    A conservative estimation indicates that more than 400 000 Latin American immigrants are living in Italy. Several studies have shown that among these, the prevalence of Chagas disease is between 3.9% and 17%, so it is not unlikely to find a patient with this disease during a cardiology visit. How many patients from Latin America are diagnosed with heart failure in Italy and no one has ever thought about a possible Chagas disease? This brief review describes the situation of the disease in Italy, its characteristics, the etiology of this disease and its treatment. The latter aspect will be discussed considering the recent published results of the BENEFIT study, where it was found that treatment with benznidazole in patients with Chagas' cardiomyopathy is able to reduce significantly the detection of parasites in the blood, but it is not able to prevent clinical deterioration during 5 years of follow-up. The possible implications of these results will be discussed. PMID:27310907

  8. Evolution of Chagas disease screening programs and control programs: historical perspective.

    PubMed

    Dias, João Carlos Pinto

    2015-09-01

    Chagas disease remains an important health problem in Latin America, affecting approximately 8 million to 10 million individuals. This disease originated from an ancient enzootic cycle, and human infection has been detected in 4,000- to 9,000-year-old mummies and has expanded with European colonization, reaching its peak prevalence in the 20th century. Discovered in 1909, the disease remained obscure and uncontrolled until the 1950s, when the generalization of serology, the characterization of chronic cardiomyopathy, and effective insecticides began. By the 1960s, national control programs were launched and incidence began to decrease as a result. During this time, scientific improvements became increasingly available to address disease management. Presently, challenges in managing Chagas disease include maintaining sustainable epidemiological surveillance, the spread of the disease to nonendemic countries, the apparent spread of oral transmission, and new symptoms and manifestations. This review discusses the possibilities and challenges in facing Chagas disease in the coming decades.

  9. [Control of Chagas disease in pregnant Latin-American women and her children].

    PubMed

    Merino, Francisco J; Martínez-Ruiz, Rocío; Olabarrieta, Iciar; Merino, Paloma; García-Bujalance, Silvia; Gastañaga, Teresa; Flores-Chavez, María

    2013-09-01

    Chagas disease is a chronic and systemic infection caused by Trypanosoma cruzi. According to estimates from WHO, 10 million people are affected by this parasite. In the last years, birthrate among the immigrant women from Latin America settled in the Comunidad Autónoma de Madrid has been increasing, and as T. cruzi can be transmitted from mother to child, in fact 11 cases of congenital Chagas disease have been confirmed. Therefore, the aim of this paper is encouraging improvements in the coverage of the anti-T. cruzi antibodies detection in pregnant women from endemic areas. By this strategy, an active search for infected pregnant women and early detection of her infected newborns could be conducted, and then an early specific treatment could be administrated. Thus, there could be an important contribution to the control of Chagas disease in non-endemic area.

  10. [Control of Chagas disease in pregnant Latin-American women and her children].

    PubMed

    Merino, Francisco J; Martínez-Ruiz, Rocío; Olabarrieta, Iciar; Merino, Paloma; García-Bujalance, Silvia; Gastañaga, Teresa; Flores-Chavez, María

    2013-09-01

    Chagas disease is a chronic and systemic infection caused by Trypanosoma cruzi. According to estimates from WHO, 10 million people are affected by this parasite. In the last years, birthrate among the immigrant women from Latin America settled in the Comunidad Autónoma de Madrid has been increasing, and as T. cruzi can be transmitted from mother to child, in fact 11 cases of congenital Chagas disease have been confirmed. Therefore, the aim of this paper is encouraging improvements in the coverage of the anti-T. cruzi antibodies detection in pregnant women from endemic areas. By this strategy, an active search for infected pregnant women and early detection of her infected newborns could be conducted, and then an early specific treatment could be administrated. Thus, there could be an important contribution to the control of Chagas disease in non-endemic area. PMID:24080893

  11. Jones matrix formulation of a Porro prism laser resonator with waveplates: theoretical and experimental analysis

    NASA Astrophysics Data System (ADS)

    Agrawal, L.; Bhardwaj, A.; Pal, S.; Kumar, A.

    2007-11-01

    This article presents the results of a detailed theoretical and experimental analysis carried out on a folded Z-shaped polarization coupled, electro-optically Q-switched laser resonator with Porro prisms and waveplates. The advantages of adding waveplates in a Porro prism resonator have been explored for creating high loss condition prior to Q-switching and obtaining variable reflectivity with fixed orientation of Porro prism. Generalized expressions have been derived in terms of azimuth angles and phase shifts introduced by the polarizing elements. These expressions corroborate with known reported results under appropriate substitutions. A specific case of a crossed Porro prism diode-pumped Nd:YAG laser has been theoretically and experimentally investigated. In the feedback arm, a 0.57λ waveplate oriented at 135° completely compensates the phase shift of a fused silica Porro prism and provides better tolerances than a BK-7 prism/0.60λ waveplate combination to stop prelasing. The fused silica prism/0.57λ combination with waveplate at 112° acts like a 100% mirror and was utilized for optimization of free running performance. The effective reflectivity was determined for various orientations of the quarter waveplate in the gain arm to numerically estimate the Q-switched laser pulse parameters through rate equation analysis. Experimental results match well with the theoretical analysis.

  12. [Improving laser center wavelength detection accuracy based on multi-level combination prisms].

    PubMed

    Liu, Xiao-Dong; Zhang, Zhi-Jie

    2011-08-01

    In order to improve the spectral resolution of birefringence prism under the conditions of ensuring the quality of interference fringes image, the system used multi-level combination prisms and designed the method of interferometer fringes splice. According to calculation of the interferometer fringes intensity of multi-level combination prisms, the optical path difference function and the spectrum resolution, the present paper analyzed that the least spectrum resolution is 2.875 cm(-1) in multi-level combination prisms of four prisms structure. The method of interferometer fringes splice was designed to splice the section interferometer fringes, and in experiment the size of multi-level combination prisms is 30 mm x 28 mm x 10 mm. The standard 635 nm laser for getting the interferometer fringes was dealed with. Experimental data show that the detection spectrum distribution of the 635.0 nm laser was distorted by the direct splicing of the interference fringes, while the detection spectrum distribution of the 635.0 nm laser was consistent with the standard spectrum by the method of interferometer fringes splice. So the method can effectively avoid spectrum distortion by interferometer fringes splice in multi-level combination prisms.

  13. High specificity of Trypanosoma cruzi epimastigote ribonucleoprotein as antigen in serodiagnosis of Chagas' disease.

    PubMed Central

    Solana, M E; Katzin, A M; Umezawa, E S; Miatello, C S

    1995-01-01

    We assessed the performance of an enzyme-linked immunosorbent assay (ELISA) with the Trypanosoma cruzi epimastigote ribosomal fraction (Tulahuen and Y strains) in order to improve the diagnostic specificity of the test. A total of 100 serum samples from patients with chronic Chagas' disease from Brazil and Argentina were studied. Sera from 116 patients, without Chagas' disease, including 10 with active mucocutaneous leishmaniasis and 20 with visceral leishmaniasis, were used as controls. Immunoglobulin G (IgG) antibodies against the ribosomal fraction (ribonucleoproteins [RNPs]) in the ELISA were found in 97% of samples from patients with Chagas' disease. A total of 99% of the sera from patients without the disease were negative, including sera from patients with mucocutaneous and visceral leishmaniases. The distribution of IgG isotypes in randomly chosen serum samples was determined by ELISA; IgG1 and IgG3 were predominant (100% exhibited IgG1 and 85% exhibited IgG3, and 50% also presented the IgG2 isotype. The distribution of the IgG subclasses was confirmed by the Western blot (immunoblot) technique. When total IgG was assayed by Western blot assay, no correlation was found between the pattern of serum reactivity and the clinical features of the patients with Chagas' disease. Therefore, no typical profile of polypeptide recognition could be associated with any clinical form of Chagas' disease (cardiomyopathy or megaviscera). Our results showed that sera from patients with Chagas' disease react with ribosomal antigens and display a typical profile of IgG isotypes (IgG1 plus IgG3).(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7650167

  14. Adaptation to Leftward-shifting Prisms Enhances Local Processing in Healthy Individuals

    PubMed Central

    Reed, Scott A.; Dassonville, Paul

    2014-01-01

    In healthy individuals, adaptation to left-shifting prisms has been shown to simulate the symptoms of hemispatial neglect, including a reduction in global processing that approximates the local bias observed in neglect patients. The current study tested whether leftward prism adaptation can more specifically enhance local processing abilities. In three experiments, the impact of local and global processing was assessed through tasks that measure susceptibility to illusions that are known to be driven by local or global contextual effects. Susceptibility to the rod-and-frame illusion – an illusion disproportionately driven by both local and global effects depending on frame size – was measured before and after adaptation to left- and right-shifting prisms. A significant increase in rod-and-frame susceptibility was found for the left-shifting prism group, suggesting that adaptation caused an increase in local processing effects. The results of a second experiment confirmed that leftward prism adaptation enhances local processing, as assessed with susceptibility to the simultaneous-tilt illusion. A final experiment employed a more specific measure of the global effect typically associated with the rod-andframe illusion, and found that although the global effect was somewhat diminished after leftward prism adaptation, the trend failed to reach significance (p = .078). Rightward prism adaptation had no significant effects on performance in any of the experiments. Combined, these findings indicate that leftward prism adaptation in healthy individuals can simulate the local processing bias of neglect patients primarily through an increased sensitivity to local visual cues, and confirm that prism adaptation not only modulates lateral shifts of attention, but also prompts shifts from one level of processing to another. PMID:24560913

  15. Exploring the effects of ecological activities during exposure to optical prisms in healthy individuals.

    PubMed

    Fortis, Paola; Ronchi, Roberta; Calzolari, Elena; Gallucci, Marcello; Vallar, Giuseppe

    2013-01-01

    Prism adaptation improves a wide range of manifestations of left spatial neglect in right-brain-damaged patients. The typical paradigm consists in repeated pointing movements to visual targets, while patients wear prism goggles that displace the visual scene rightwards. Recently, we demonstrated the efficacy of a novel adaptation procedure, involving a variety of every-day visuo-motor activities. This "ecological" procedure proved to be as effective as the repetitive pointing adaptation task in ameliorating symptoms of spatial neglect, and was better tolerated by patients. However, the absence of adaptation and aftereffects measures for the ecological treatment did not allow for a full comparison of the two procedures. This is important in the light of recent findings showing that the magnitude of prism-induced aftereffects may predict recovery from spatial neglect. Here, we investigated prism-induced adaptation and aftereffects after ecological and pointing adaptation procedures. Forty-eight neurologically healthy participants (young and aged groups) were exposed to rightward shifting prisms while they performed the ecological or the pointing procedures, in separate days. Before and after prism exposure, participants performed proprioceptive, visual, and visual-proprioceptive tasks to assess prism-induced aftereffects. Participants adapted to the prisms during both procedures. Importantly, the ecological procedure induced greater aftereffects in the proprioceptive task (for both the young and the aged groups) and in the visual-proprioceptive task (young group). A similar trend was found for the visual task in both groups. Finally, participants rated the ecological procedure as more pleasant, less monotonous, and more sustainable than the pointing procedure. These results qualify ecological visuo-motor activities as an effective prism-adaptation procedure, suitable for the rehabilitation of spatial neglect.

  16. Adaptation to leftward-shifting prisms enhances local processing in healthy individuals.

    PubMed

    Reed, Scott A; Dassonville, Paul

    2014-04-01

    In healthy individuals, adaptation to left-shifting prisms has been shown to simulate the symptoms of hemispatial neglect, including a reduction in global processing that approximates the local bias observed in neglect patients. The current study tested whether leftward prism adaptation can more specifically enhance local processing abilities. In three experiments, the impact of local and global processing was assessed through tasks that measure susceptibility to illusions that are known to be driven by local or global contextual effects. Susceptibility to the rod-and-frame illusion - an illusion disproportionately driven by both local and global effects depending on frame size - was measured before and after adaptation to left- and right-shifting prisms. A significant increase in rod-and-frame susceptibility was found for the left-shifting prism group, suggesting that adaptation caused an increase in local processing effects. The results of a second experiment confirmed that leftward prism adaptation enhances local processing, as assessed with susceptibility to the simultaneous-tilt illusion. A final experiment employed a more specific measure of the global effect typically associated with the rod-and-frame illusion, and found that although the global effect was somewhat diminished after leftward prism adaptation, the trend failed to reach significance (p=.078). Rightward prism adaptation had no significant effects on performance in any of the experiments. Combined, these findings indicate that leftward prism adaptation in healthy individuals can simulate the local processing bias of neglect patients primarily through an increased sensitivity to local visual cues, and confirm that prism adaptation not only modulates lateral shifts of attention, but also prompts shifts from one level of processing to another.

  17. Anti-triatomine saliva immunoassays for the evaluation of impregnated netting trials against Chagas disease transmission

    PubMed Central

    Schwarz, Alexandra; Juarez, Jenny Ancca; Richards, Jean; Rath, Bruno; Machaca, Victor Quispe; Castro, Yagahira E.; Málaga, Edith S.; Levy, Katelyn; Gilman, Robert H.; Bern, Caryn; Verastegui, Manuela; Levy, Michael Z.

    2011-01-01

    Insecticide-impregnated nets can kill triatomine bugs, but it remains unclear whether they can protect against Chagas disease transmission. In a field trial in Quequeña, Peru, sentinel guinea pigs placed in intervention enclosures covered by deltamethrin-treated nets showed significantly lower antibody responses to saliva of Triatoma infestans compared with animals placed in pre-existing control enclosures. Our results strongly suggest that insecticide-treated nets prevent triatomine bites and can thereby protect against infection with Trypanosoma cruzi. Anti-salivary immunoassays are powerful new tools to evaluate intervention strategies against Chagas disease. PMID:21426907

  18. Should trypanocidal therapy be used to treat patients in the chronic phase of Chagas disease?

    PubMed

    Popoff, Federico; Izcovich, Ariel

    2015-10-26

    Antiparasitic treatment of patients with Chagas’ disease in chronic stage could prevent the complications related to the disease. Searching in Epistemonikos database, which is maintained by screening 30 databases, we identified five systematic reviews including eight randomized trials and 11 observational studies. We combined the evidence using meta-analysis and generated a summary of findings table following the GRADE approach. We concluded it is not clear whether antiparasitic treatment improves survival or reduces complications related to chronic Chagas’ disease because the certainty of the evidence is very low.

  19. Drug discovery for Chagas disease should consider Trypanosoma cruzi strain diversity

    PubMed Central

    Zingales, Bianca; Miles, Michael A; Moraes, Carolina B; Luquetti, Alejandro; Guhl, Felipe; Schijman, Alejandro G; Ribeiro, Isabela

    2014-01-01

    This opinion piece presents an approach to standardisation of an important aspect of Chagas disease drug discovery and development: selecting Trypanosoma cruzi strains for in vitro screening. We discuss the rationale for strain selection representing T. cruzi diversity and provide recommendations on the preferred parasite stage for drug discovery, T. cruzi discrete typing units to include in the panel of strains and the number of strains/clones for primary screens and lead compounds. We also consider experimental approaches for in vitro drug assays. The Figure illustrates the current Chagas disease drug-discovery and development landscape. PMID:25317712

  20. Anti-triatomine saliva immunoassays for the evaluation of impregnated netting trials against Chagas disease transmission.

    PubMed

    Schwarz, Alexandra; Juarez, Jenny Ancca; Richards, Jean; Rath, Bruno; Machaca, Victor Quispe; Castro, Yagahira E; Málaga, Edith S; Levy, Katelyn; Gilman, Robert H; Bern, Caryn; Verastegui, Manuela; Levy, Michael Z

    2011-05-01

    Insecticide-impregnated nets can kill triatomine bugs, but it remains unclear whether they can protect against Chagas disease transmission. In a field trial in Quequeña, Peru, sentinel guinea pigs placed in intervention enclosures covered by deltamethrin-treated nets showed significantly lower antibody responses to saliva of Triatoma infestans compared with animals placed in pre-existing control enclosures. Our results strongly suggest that insecticide-treated nets prevent triatomine bites and can thereby protect against infection with Trypanosoma cruzi. Anti-salivary immunoassays are powerful new tools to evaluate intervention strategies against Chagas disease.

  1. A bi-prism interferometer for hard x-ray photons

    SciTech Connect

    Isakovic, A.F.; Siddons, D.; Stein, A.; Warren, J.B.; Sandy, A.R.; Narayanan, M.S.; Ablett, J.M.; Metzler, M. and Evans-Lutterodt, K.

    2010-04-06

    Micro-fabricated bi-prisms have been used to create an interference pattern from an incident hard X-ray beam, and the intensity of the pattern probed with fluorescence from a 30 nm-thick metal film. Maximum fringe visibility exceeded 0.9 owing to the nano-sized probe and the choice of single-crystal prism material. A full near-field analysis is necessary to describe the fringe field intensities, and the transverse coherence lengths were extracted at APS beamline 8-ID-I. It is also shown that the maximum number of fringes is dependent only on the complex refractive index of the prism material.

  2. Properties of YMnO{sub 3} self-assembled nanocrystalline prisms on GaN

    SciTech Connect

    Keenan, Cameron; Chandril, Sandeep; Myers, Thomas H.; Lederman, David; Ramos-Moore, E.; Cabrera, A. L.

    2008-01-07

    Growth of YMnO{sub 3} on GaN (0001) using molecular beam epitaxy at temperatures greater than 850 deg. C resulted in the spontaneous formation of crystalline prisms, ranging from 20 to 60 nm in height and 50 to 500 nm in lateral size, surrounded by a 6 nm thick continuous YMnO{sub 3} film. The local dielectric properties were measured using scanning surface probe microscopy. The prisms were ferroelectric at room temperature and their ferroelectric properties were enhanced for taller prisms. This is consistent with these structures being less constrained than the continuous layer, which is clamped by the surrounding unpolarized film.

  3. Post-self-assembly covalent chemistry of discrete multicomponent metallosupramolecular hexagonal prisms.

    PubMed

    Wang, Ming; Lan, Wen-Jie; Zheng, Yao-Rong; Cook, Timothy R; White, Henry S; Stang, Peter J

    2011-07-20

    The multicomponent coordination-driven self-assembly of hexakis[4-(4-pyridyl)phenyl]benzene, cis-(PEt(3))(2)Pt(II)(OTf)(2), and amine- or maleimide-functionalized isophthalate forms discrete hexagonal prisms as single reaction products. The amino or maleimide groups decorating the isophthalate pillars of the prisms provide reactive sites for post-self-asssembly modifications. In this communication, we demonstrate that the hexagonal prisms can be functionalized without disrupting the prismatic cores, enabling the incorporation of new functionalities under mild conditions.

  4. CLESSIDRA: Focusing Hard X-Rays Efficiently with Arrays Composed of Small Prisms

    SciTech Connect

    Jark, Werner; Perennes, Frederic; Matteucci, Marco; Mancini, Lucia; Menk, Ralf H.; Rigon, Luigi

    2007-01-19

    Small prisms arranged such that the number of prisms to traverse by an x-ray beam is linearly increasing with distance from the symmetry axis of the device will direct an incident wave to a common cross over point. This structure can be understood as a special form of the Fresnel version of a concave refractive x-ray lens. Indeed it is obtained by removing blocks of optically passive material of equal height from the concave lens shape. It will be shown that the structure has a high refraction efficiency and that the losses are produced by problems in the fabrication of sufficiently sharp tips for the prisms.

  5. Volumetric display using rotating prism sheets arranged in a symmetrical configuration.

    PubMed

    Maeda, Yuki; Miyazaki, Daisuke; Mukai, Takaaki; Maekawa, Satoshi

    2013-11-01

    A volumetric display that creates a distortion-free three-dimensional (3D) image in midair is described. The proposed system consists of rotating prism sheets used as an optical scanner and a dihedral corner reflector array (DCRA), which is a distortion-free imaging element. Two prism sheets are arranged in a symmetrical configuration to reduce an unnatural motion parallax caused by optical aberrations. A cross-section of the 3D image is formed by the DCRA in midair and moved by the rotating prism sheets to create a 3D displayable space. A 3D volume image was displayed without image distortion or unnatural motion parallax.

  6. Molecular Epidemiology of Human Oral Chagas Disease Outbreaks in Colombia

    PubMed Central

    Ramírez, Juan David; Montilla, Marleny; Cucunubá, Zulma M.; Floréz, Astrid Carolina; Zambrano, Pilar; Guhl, Felipe

    2013-01-01

    Background Trypanosoma cruzi, the causative agent of Chagas disease, displays significant genetic variability revealed by six Discrete Typing Units (TcI-TcVI). In this pathology, oral transmission represents an emerging epidemiological scenario where different outbreaks associated to food/beverages consumption have been reported in Argentina, Bolivia, Brazil, Ecuador and Venezuela. In Colombia, six human oral outbreaks have been reported corroborating the importance of this transmission route. Molecular epidemiology of oral outbreaks is barely known observing the incrimination of TcI, TcII, TcIV and TcV genotypes. Methodology and Principal Findings High-throughput molecular characterization was conducted performing MLMT (Multilocus Microsatellite Typing) and mtMLST (mitochondrial Multilocus Sequence Typing) strategies on 50 clones from ten isolates. Results allowed observing the occurrence of TcI, TcIV and mixed infection of distinct TcI genotypes. Thus, a majority of specific mitochondrial haplotypes and allelic multilocus genotypes associated to the sylvatic cycle of transmission were detected in the dataset with the foreseen presence of mitochondrial haplotypes and allelic multilocus genotypes associated to the domestic cycle of transmission. Conclusions These findings suggest the incrimination of sylvatic genotypes in the oral outbreaks occurred in Colombia. We observed patterns of super-infection and/or co-infection with a tailored association with the severe forms of myocarditis in the acute phase of the disease. The transmission dynamics of this infection route based on molecular epidemiology evidence was unraveled and the clinical and biological implications are discussed. PMID:23437405

  7. Insecticide resistance in vector Chagas disease: evolution, mechanisms and management.

    PubMed

    Mougabure-Cueto, Gastón; Picollo, María Inés

    2015-09-01

    Chagas disease is a chronic parasitic infection restricted to America. The disease is caused by the protozoa Trypanosoma cruzi, which is transmitted to human through the feces of infected triatomine insects. Because no treatment is available for the chronic forms of the disease, vector chemical control represents the best way to reduce the incidence of the disease. Chemical control has been based principally on spraying dwellings with insecticide formulations and led to the reduction of triatomine distribution and consequent interruption of disease transmission in several areas from endemic region. However, in the last decade it has been repeatedly reported the presence triatomnes, mainly Triatoma infestans, after spraying with pyrethroid insecticides, which was associated to evolution to insecticide resistance. In this paper the evolution of insecticide resistance in triatomines is reviewed. The insecticide resistance was detected in 1970s in Rhodnius prolixus and 1990s in R. prolixus and T. infestans, but not until the 2000s resistance to pyrthroids in T. infestans associated to control failures was described in Argentina and Bolivia. The main resistance mechanisms (i.e. enhanced metabolism, altered site of action and reduced penetration) were described in the T. infestans resistant to pyrethrods. Different resistant profiles were demonstrated suggesting independent origin of the different resistant foci of Argentina and Bolivia. The deltamethrin resistance in T. infestans was showed to be controlled by semi-dominant, autosomally inherited factors. Reproductive and developmental costs were also demonstrated for the resistant T. infestans. A discussion about resistance and tolerance concepts and the persistence of T. infestans in Gran Chaco region are presented. In addition, theoretical concepts related to toxicological, evolutionary and ecological aspects of insecticide resistance are discussed in order to understand the particular scenario of pyrethroid

  8. [Congenital Chagas disease in the city of Salta, Argentina].

    PubMed

    Zaidenberg, M; Segovia, A

    1993-01-01

    The immune response to Trypanosoma cruzi was studied in our hospital in 937 pregnant women(PW) and their 929 newborns(NB), group I; 4 NB from this center not included in the first group, group II and 35 NB derived from other centers, group III. Two positive results among indirect hemagglutination (IHA), complement fixation(CF) and indirect hemagglutination(IHA), complement fixation(CF) and indirect immunofluorescence(IIF) tests were considered as the criterion of previous infection with T. cruzi in PW. The presence of T. cruzi in blood, explored in fresh smears by serial micro-hematocrite and/or by xenodiagnosis, was the only criterion to define infection in NB. All NB were followed up by direct agglutination (DA) with or without 2 mercaptoethanol (DA-w2ME, DA-wo2ME) and IIF in order to establish the specific antibody kinetics. Clinical studies on NB with T. cruzi infection include routine laboratory tests. Benznidazole (3 to 7 mg/kg/day) and, in 1 case, nifurtimox (15 mg/kg/day) were employed as therapeutic agents. T. cruzi infection was confirmed in 149 PW(15.9%), table I. These chagasic mothers delivered 6 chagasic NB (CCHD-NB), (4%). Diagnosis of congenital Chagas' disease accounted for a total of 12 NB out of the 968 studied. 4 out of them were positive by both microhematocrite and blood smears and 7 by microhematocrite alone. Xenodiagnosis was performed in 2 NB resulting positive in both cases, table II. The most usual clinical findings included hepatomegaly (present in all cases), splenomegaly 8/12, jaundice 10/12 and prematurity 5/12, table 3. Laboratory findings showed anemia to be of hypochromic microcytic type in all cases.(ABSTRACT TRUNCATED AT 250 WORDS)

  9. Insecticide resistance in vector Chagas disease: evolution, mechanisms and management.

    PubMed

    Mougabure-Cueto, Gastón; Picollo, María Inés

    2015-09-01

    Chagas disease is a chronic parasitic infection restricted to America. The disease is caused by the protozoa Trypanosoma cruzi, which is transmitted to human through the feces of infected triatomine insects. Because no treatment is available for the chronic forms of the disease, vector chemical control represents the best way to reduce the incidence of the disease. Chemical control has been based principally on spraying dwellings with insecticide formulations and led to the reduction of triatomine distribution and consequent interruption of disease transmission in several areas from endemic region. However, in the last decade it has been repeatedly reported the presence triatomnes, mainly Triatoma infestans, after spraying with pyrethroid insecticides, which was associated to evolution to insecticide resistance. In this paper the evolution of insecticide resistance in triatomines is reviewed. The insecticide resistance was detected in 1970s in Rhodnius prolixus and 1990s in R. prolixus and T. infestans, but not until the 2000s resistance to pyrthroids in T. infestans associated to control failures was described in Argentina and Bolivia. The main resistance mechanisms (i.e. enhanced metabolism, altered site of action and reduced penetration) were described in the T. infestans resistant to pyrethrods. Different resistant profiles were demonstrated suggesting independent origin of the different resistant foci of Argentina and Bolivia. The deltamethrin resistance in T. infestans was showed to be controlled by semi-dominant, autosomally inherited factors. Reproductive and developmental costs were also demonstrated for the resistant T. infestans. A discussion about resistance and tolerance concepts and the persistence of T. infestans in Gran Chaco region are presented. In addition, theoretical concepts related to toxicological, evolutionary and ecological aspects of insecticide resistance are discussed in order to understand the particular scenario of pyrethroid

  10. Community Participation in Chagas Disease Vector Surveillance: Systematic Review

    PubMed Central

    Abad-Franch, Fernando; Vega, M. Celeste; Rolón, Miriam S.; Santos, Walter S.; Rojas de Arias, Antonieta

    2011-01-01

    Background Vector control has substantially reduced Chagas disease (ChD) incidence. However, transmission by household-reinfesting triatomines persists, suggesting that entomological surveillance should play a crucial role in the long-term interruption of transmission. Yet, infestation foci become smaller and harder to detect as vector control proceeds, and highly sensitive surveillance methods are needed. Community participation (CP) and vector-detection devices (VDDs) are both thought to enhance surveillance, but this remains to be thoroughly assessed. Methodology/Principal Findings We searched Medline, Web of Knowledge, Scopus, LILACS, SciELO, the bibliographies of retrieved studies, and our own records. Data from studies describing vector control and/or surveillance interventions were extracted by two reviewers. Outcomes of primary interest included changes in infestation rates and the detection of infestation/reinfestation foci. Most results likely depended on study- and site-specific conditions, precluding meta-analysis, but we re-analysed data from studies comparing vector control and detection methods whenever possible. Results confirm that professional, insecticide-based vector control is highly effective, but also show that reinfestation by native triatomines is common and widespread across Latin America. Bug notification by householders (the simplest CP-based strategy) significantly boosts vector detection probabilities; in comparison, both active searches and VDDs perform poorly, although they might in some cases complement each other. Conclusions/Significance CP should become a strategic component of ChD surveillance, but only professional insecticide spraying seems consistently effective at eliminating infestation foci. Involvement of stakeholders at all process stages, from planning to evaluation, would probably enhance such CP-based strategies. PMID:21713022

  11. Modulation of immune response in experimental Chagas disease

    PubMed Central

    Basso, Beatriz

    2013-01-01

    Trypanosoma cruzi (T. cruzi), the etiological agent of Chagas disease, affects nearly 18 million people in Latin America and 90 million are at risk of infection. The parasite presents two stages of medical importance in the host, the amastigote, intracellular replicating form, and the extracellular trypomastigote, the infective form. Thus infection by T. cruzi induces a complex immune response that involves effectors and regulatory mechanisms. That is why control of the infection requires a strong humoral and cellular immune response; hence, the outcome of host-parasite interaction in the early stages of infection is extremely important. A critical event during this period of the infection is innate immune response, in which the macrophage’s role is vital. Thus, after being phagocytized, the parasite is able to develop intracellularly; however, during later periods, these cells induce its elimination by means of toxic metabolites. In turn, as the infection progresses, adaptive immune response mechanisms are triggered through the TH1 and TH2 responses. Finally, T. cruzi, like other protozoa such as Leishmania and Toxoplasma, have numerous evasive mechanisms to the immune response that make it possible to spread around the host. In our Laboratory we have developed a vaccination model in mice with Trypanosoma rangeli, nonpathogenic to humans, which modulates the immune response to infection by T. cruzi, thus protecting them. Vaccinated animals showed an important innate response (modulation of NO and other metabolites, cytokines, activation of macrophages), a strong adaptive cellular response and significant increase in specific antibodies. The modulation caused early elimination of the parasites, low parasitaemia, the absence of histological lesions and high survival rates. Even though progress has been made in the knowledge of some of these mechanisms, new studies must be conducted which could target further prophylactic and therapeutic trials against T. cruzi

  12. Barriers to Treatment Access for Chagas Disease in Mexico

    PubMed Central

    Manne, Jennifer M.; Snively, Callae S.; Ramsey, Janine M.; Salgado, Marco Ocampo; Bärnighausen, Till; Reich, Michael R.

    2013-01-01

    Background According to World Health Organization (WHO) prevalence estimates, 1.1 million people in Mexico are infected with Trypanosoma cruzi, the etiologic agent of Chagas disease (CD). However, limited information is available about access to antitrypanosomal treatment. This study assesses the extent of access in Mexico, analyzes the barriers to access, and suggests strategies to overcome them. Methods and Findings Semi-structured in-depth interviews were conducted with 18 key informants and policymakers at the national level in Mexico. Data on CD cases, relevant policy documents and interview data were analyzed using the Flagship Framework for Pharmaceutical Policy Reform policy interventions: regulation, financing, payment, organization, and persuasion. Data showed that 3,013 cases were registered nationally from 2007–2011, representing 0.41% of total expected cases based on Mexico's national prevalence estimate. In four of five years, new registered cases were below national targets by 11–36%. Of 1,329 cases registered nationally in 2010–2011, 834 received treatment, 120 were pending treatment as of January 2012, and the treatment status of 375 was unknown. The analysis revealed that the national program mainly coordinated donation of nifurtimox and that important obstacles to access include the exclusion of antitrypanosomal medicines from the national formulary (regulation), historical exclusion of CD from the social insurance package (organization), absence of national clinical guidelines (organization), and limited provider awareness (persuasion). Conclusions Efforts to treat CD in Mexico indicate an increased commitment to addressing this disease. Access to treatment could be advanced by improving the importation process for antitrypanosomal medicines and adding them to the national formulary, increasing education for healthcare providers, and strengthening clinical guidelines. These recommendations have important implications for other countries in

  13. Antimutagenic effects of subfractions of Chaga mushroom (Inonotus obliquus) extract.

    PubMed

    Ham, Seung-Shi; Kim, Soo-Hyun; Moon, Sun-Young; Chung, Mi Ja; Cui, Cheng-Bi; Han, Eun-Kyung; Chung, Cha-Kwon; Choe, Myeon

    2009-01-01

    Inonotus obliquus is a mushroom commonly known as Chaga that is widely used in folk medicine in Siberia, North America, and North Europe. Here, we evaluated the antimutagenic and antioxidant capacities of subfractions of Inonotus obliquus extract. The ethyl acetate extract was separated by vacuum chromatography into three fractions, and the fraction bearing the highest antimutagenic activity was subsequently separated into four fractions by reversed phase (ODS-C18) column chromatography. The most antimutagenic fraction was then separated into two subfractions (subfractions 1 and 2) by normal phase silica gel column chromatography. Ames test analysis revealed that the subfractions were not mutagenic. At 50 μg/plate, subfractions 1 and 2 strongly inhibited the mutagenesis induced in Salmonella typhimurium strain TA100 by the directly acting mutagen MNNG (0.4 μg/plate) by 80.0% and 77.3%, respectively. They also inhibited 0.15 μg/plate 4NQO-induced mutagenesis in TA98 and TA100 by 52.6-62.0%. The mutagenesis in TA98 induced by the indirectly acting mutagens Trp-P-1 (0.15 μg/plate) and B(α)P (10 μg/plate) was reduced by 47.0-68.2% by the subfractions, while the mutagenesis in TA100 by Trp-P-1 and B(α)P was reduced by 70.5-87.2%. Subfraction 1 was more inhibitory than subfraction 2 with regard to the mutagenic effects of 4NQO, Trp-P-1, and B(α)P. Subfractions 1 and 2 also had a strong antioxidant activity against DPPH radicals and were identified by MS, 1H NMR and 13C NMR analyses as 3β-hydroxy-lanosta-8, 24-dien-21-al and inotodiol, respectively. Thus, we show that the 3beta-hydroxy-lanosta-8, 24-dien-21-al and inotodiol components of Inonotus obliquus bear antimutagenic and antioxidative activities. PMID:18992843

  14. Effects of aspirin-triggered resolvin D1 on peripheral blood mononuclear cells from patients with Chagas' heart disease.

    PubMed

    Ogata, Haline; Teixeira, Maxelle Martins; Sousa, Rodrigo Cunha de; Silva, Marcos Vinícius da; Correia, Dalmo; Rodrigues Junior, Virmondes; Levy, Bruce David; Rogério, Alexandre de Paula

    2016-04-15

    Chagas disease is caused by Trypanosoma cruzi (T. cruzi). In some patients with Chagas disease, symptoms progress to chronic chagasic cardiomyopathy. Endogenously, inflammation is resolved in the presence of lipid mediators such as aspirin-triggered RvD1 (AT-RvD1) which has anti-inflammatory and pro-resolution effects. Here, we demonstrated, for the first time, the effects of AT-RvD1 on T. cruzi antigen-stimulated peripheral blood mononuclear cells (PBMCs) from patients with Chagas heart disease. The levels of IFN-γ, TNF-α, IL-10, and IL-13 increased in PBMCs from cardiac-form Chagas patients in stage B1 (patients with fewer heart abnormalities) stimulated with T. cruzi antigen compared to those in non-stimulated PBMCs. AT-RvD1 reduced the IFN-γ concentrations in PBMCs from patients with Chagas disease stimulated with T. cruzi antigen compared to stimulated with T. cruzi antigen cells. AT-RvD1 treatment resulted in no observable changes in TNF-α, IL-10, and IL-13 levels. AT-RvD1 significantly decreased the percentage of necrotic cells and caused a significant reduction in the proliferation rate of T. cruzi antigen-stimulated PBMCs from patients with Chagas disease. These findings demonstrate that AT-RvD1 modulates the immune response in Chagas disease patients and might have potential to be used as an alternative approach for slowing the development of further heart damage.

  15. FC-TRIPLEX Chagas/Leish IgG1: A Multiplexed Flow Cytometry Method for Differential Serological Diagnosis of Chagas Disease and Leishmaniasis

    PubMed Central

    Teixeira-Carvalho, Andréa; Campos, Fernanda Magalhães Freire; Geiger, Stefan Michael; Rocha, Roberta Dias Rodrigues; de Araújo, Fernanda Fortes; Vitelli-Avelar, Danielle Marquete; Andrade, Mariléia Chaves; Araújo, Márcio Sobreira Silva; Lemos, Elenice Moreira; de Freitas Carneiro Proietti, Anna Bárbara; Sabino, Ester Cerdeira; Caldas, Rafaella Gaiotti; Freitas, Carolina Renata Camargos; Campi-Azevedo, Ana Carolina; Elói-Santos, Silvana Maria; Martins-Filho, Olindo Assis

    2015-01-01

    Differential serological diagnosis of Chagas disease and leishmaniasis is difficult owing to cross-reactivity resulting from the fact that the parasites that cause these pathologies share antigenic epitopes. Even with optimized serological assays that use parasite-specific recombinant antigens, inconclusive test results continue to be a problem. Therefore, new serological tests with high sensitivity and specificity are needed. In the present work, we developed and evaluated the performance of a new flow cytometric serological method, referred to as FC-TRIPLEX Chagas/Leish IgG1, for the all-in-one classification of inconclusive tests. The method uses antigens for the detection of visceral leishmaniasis, localized cutaneous leishmaniasis, and Chagas disease and is based on an inverted detuned algorithm for analysis of anti-Trypanosomatidae IgG1 reactivity. First, parasites were label with fluorescein isothiocyanate or Alexa Fluor 647 at various concentrations. Then serum samples were serially diluted, the dilutions were incubated with suspensions of mixed labeled parasites, and flow cytometric measurements were performed to determine percentages of positive fluorescent parasites. Using the new method, we obtained correct results for 76 of 80 analyzed serum samples (95% overall performance), underscoring the outstanding performance of the method. Moreover, we found that the fluorescently labeled parasite suspensions were stable during storage at room temperature, 4°C, and –20°C for 1 year. In addition, two different lots of parasite suspensions showed equivalent antigen recognition; that is, the two lots showed equivalent categorical segregation of anti-Trypanosomatidae IgG1 reactivity at selected serum dilutions. In conclusion, we have developed a sensitive and selective method for differential diagnosis of Chagas disease, visceral leishmaniasis, and localized cutaneous leishmaniasis. PMID:25875961

  16. FC-TRIPLEX Chagas/Leish IgG1: a multiplexed flow cytometry method for differential serological diagnosis of chagas disease and leishmaniasis.

    PubMed

    Teixeira-Carvalho, Andréa; Campos, Fernanda Magalhães Freire; Geiger, Stefan Michael; Rocha, Roberta Dias Rodrigues; de Araújo, Fernanda Fortes; Vitelli-Avelar, Danielle Marquete; Andrade, Mariléia Chaves; Araújo, Márcio Sobreira Silva; Lemos, Elenice Moreira; de Freitas Carneiro Proietti, Anna Bárbara; Sabino, Ester Cerdeira; Caldas, Rafaella Gaiotti; Freitas, Carolina Renata Camargos; Campi-Azevedo, Ana Carolina; Elói-Santos, Silvana Maria; Martins-Filho, Olindo Assis

    2015-01-01

    Differential serological diagnosis of Chagas disease and leishmaniasis is difficult owing to cross-reactivity resulting from the fact that the parasites that cause these pathologies share antigenic epitopes. Even with optimized serological assays that use parasite-specific recombinant antigens, inconclusive test results continue to be a problem. Therefore, new serological tests with high sensitivity and specificity are needed. In the present work, we developed and evaluated the performance of a new flow cytometric serological method, referred to as FC-TRIPLEX Chagas/Leish IgG1, for the all-in-one classification of inconclusive tests. The method uses antigens for the detection of visceral leishmaniasis, localized cutaneous leishmaniasis, and Chagas disease and is based on an inverted detuned algorithm for analysis of anti-Trypanosomatidae IgG1 reactivity. First, parasites were label with fluorescein isothiocyanate or Alexa Fluor 647 at various concentrations. Then serum samples were serially diluted, the dilutions were incubated with suspensions of mixed labeled parasites, and flow cytometric measurements were performed to determine percentages of positive fluorescent parasites. Using the new method, we obtained correct results for 76 of 80 analyzed serum samples (95% overall performance), underscoring the outstanding performance of the method. Moreover, we found that the fluorescently labeled parasite suspensions were stable during storage at room temperature, 4 °C, and -20 °C for 1 year. In addition, two different lots of parasite suspensions showed equivalent antigen recognition; that is, the two lots showed equivalent categorical segregation of anti-Trypanosomatidae IgG1 reactivity at selected serum dilutions. In conclusion, we have developed a sensitive and selective method for differential diagnosis of Chagas disease, visceral leishmaniasis, and localized cutaneous leishmaniasis.

  17. Cavity Enhanced Absorption Spectroscopy Using a Broadband Prism Cavity and a Supercontinuum Source

    NASA Astrophysics Data System (ADS)

    Johnston, Paul S.; Lehmann, Kevin K.

    2009-06-01

    The multiplex advantage of current cavity enhanced spectrometers is limited by the high reflectivity bandwidth of the mirrors used to construct the high finesse cavity. Previously, we reported the design and construction of a new spectrometer that circumvents this limitation by utilizing Brewster^{,}s angle prism retroreflectors. The prisms, made from fused silica and combined with a supercontinuum source generated by pumping a highly nonlinear photonic crystal fiber, yields a spectral window ranging from 500 nm to 1750 nm. Recent progress in the instruments development will be discussed, including work on modeling the prism cavity losses, alternative prism material for use in the UV and mid-IR spectral regions, and a new high power supercontinuum source based on mode-locked picosecond laser.

  18. Modelling and design of modified Wollaston prisms and the application in differential interference contrast microscopy

    NASA Astrophysics Data System (ADS)

    Zhang, Site; Zhong, Huiying; Wyrowski, Frank

    2016-03-01

    Wollaston prisms and the modified Wollaston prisms, which are interesting for various applications like optical metrology, topography of surfaces and biological imaging, has been theoretically studied and also been practically applied. The previous studies are mostly based on ray tracing analysis and, as a result, the information that can be obtained are somehow restricted. In this paper, we propose a geometric field tracing technique for the simulation of light propagation through Wollaston prisms. In geometric field tracing we seek for the solutions to Maxwell's equations under the geometrical optics approximation, so that all the properties of light as electromagnetic field are retained. Using the proposed simulation technique, we present the simulation of a differential interference contrast (DIC) microscopy, in which the modified Wollaston prism is used as the key component.

  19. C&O Canal prism, with towpath (left) and fill under WM ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    C&O Canal prism, with towpath (left) and fill under WM roadbed (right), milepost 142 vicinity, looking southwest. - Western Maryland Railway, Cumberland Extension, Pearre to North Branch, from WM milepost 125 to 160, Pearre, Washington County, MD

  20. Measurement of two-dimensional small angle deviation with a prism interferometer

    SciTech Connect

    Chatterjee, Sanjib; Kumar, Y. Pavan

    2008-09-20

    A new technique for the measurement of two-dimensional small angular deviation is presented. A compound prism, which effectively produces a combination of two right-angled prisms in orthogonal directions, and plane reference surfaces have been utilized for the measurement of the orthogonal components of the angular tilt of an incident plane wavefront. Each orthogonal component of the angular tilt is separately measured from the angular rotation of the resultant wedge fringes between two plane wavefronts generated due to splitting of the incident plane wavefront by the corresponding set of right-angled prism and plane reference surface. The technique is shown to have high sensitivity for the measurement of small angle deviation. A monolithic prism interferometer, which is practically insensitive to vibration, is also proposed. Results obtained for the measurement of a known tilt angle are presented.

  1. Effects of prism adaptation on motor-intentional spatial bias in neglect

    PubMed Central

    Fortis, Paola; Chen, Peii; Goedert, Kelly M.; Barrett, Anna M.

    2011-01-01

    Prism adaptation may alleviate some symptoms of spatial neglect. However, the mechanism through which this technique works is still unclear. The current study investigated whether prism adaptation differentially affects dysfunction in perceptual-attentional “where” versus motor-intentional “aiming” bias. Five neglect patients performed a line bisection task in which lines were viewed under both normal and right-left reversed viewing conditions, allowing for the fractionation of “where” and “aiming” spatial bias components. Following two consecutive days of prism adaptation, participants demonstrated a significant improvement in “aiming” spatial bias, with no effect on “where” spatial bias. These findings suggest that prism adaptation may primarily affect motor-intentional “aiming” bias in post-stroke spatial neglect patients. PMID:21817924

  2. [The effect of treatment with prisms on head position in persons with nystagmus--preliminary report].

    PubMed

    Baranowska-George, T

    1996-03-01

    The aim of the work is to inspect the influence of the treatment by using hyper-correcting prisms on the vertical deviations of the eyes and on the head's position in persons with nystagmus. We observed 4 persons with nystagmus without strabismus and 3 persons with convergent squint. In persons without strabismus the prismatic correction placed with an edge in the direction of the "calm's zone" (quiet's zone) to obtain the straight position of the head when looking forwards was applied. Twice a day during 10 minutes the patients were making the movement's exercises in the vertical and horizontal direction looking by the prism separately by each eye. This prism (often 35 D prism) was placed with the edge in the direction of greater deviation of the oblique inferior muscles and the left rectus inferior muscle. Patients with convergent strabismus were treated according to the principles of localization method with consideration of the localize exercises by using hyper-correcting prisms in the vertical and horizontal directions. Two patients had a surgery in order to eliminate not aesthetic and strong prisms which were applied because of large horizontal squint. One patient with convergent alternate squint with hyperactivity of both inferior oblique muscles and inferior rectus muscle of the left eye was treated without surgery, only by the conservative treatment with prisms. In all patients we obtained a straight position of the head despite of the nystagmus still existing during the eyes movements in some directions. The treatment by using hyper-correcting prisms can completely replace the surgical treatment or is able to supplement it and prevent relapses.

  3. Metallothionein-1 and nitric oxide expression are inversely correlated in a murine model of Chagas disease

    PubMed Central

    Gonzalez-Mejia, Martha Elba; Torres-Rasgado, Enrique; Porchia, Leonardo M; Salgado, Hilda Rosas; Totolhua, José-Luis; Ortega, Arturo; Hernández-Kelly, Luisa Clara Regina; Ruiz-Vivanco, Guadalupe; Báez-Duarte, Blanca G; Pérez-Fuentes, Ricardo

    2014-01-01

    Chagas disease, caused by Trypanosoma cruzi, represents an endemic among Latin America countries. The participation of free radicals, especially nitric oxide (NO), has been demonstrated in the pathophysiology of seropositive individuals with T. cruzi. In Chagas disease, increased NO contributes to the development of cardiomyopathy and megacolon. Metallothioneins (MTs) are efficient free radicals scavengers of NO in vitro and in vivo. Here, we developed a murine model of the chronic phase of Chagas disease using endemic T. cruzi RyCH1 in BALB/c mice, which were divided into four groups: infected non-treated (Inf), infected N-monomethyl-L-arginine treated (Inf L-NAME), non-infected L-NAME treated and non-infected vehicle-treated. We determined blood parasitaemia and NO levels, the extent of parasite nests in tissues and liver MT-I expression levels. It was observed that NO levels were increasing in Inf mice in a time-dependent manner. Inf L-NAME mice had fewer T. cruzi nests in cardiac and skeletal muscle with decreased blood NO levels at day 135 post infection. This affect was negatively correlated with an increase of MT-I expression (r = -0.8462, p < 0.0001). In conclusion, we determined that in Chagas disease, an unknown inhibitory mechanism reduces MT-I expression, allowing augmented NO levels. PMID:24676665

  4. A 4-year follow-up study of a rural community with endemic Chagas' disease*

    PubMed Central

    Puigbó, J. J.; Rhode, J. R. Nava; Barrios, H. García; Yépez, C. Gil

    1968-01-01

    The paper reports on a 4-year follow-up study that represents the continuation of a previous cross-sectional study on Chagas' disease carried out in a rural community (Belén) in Venezuela. The earlier study included 1210 persons all over 5 years of age out of a total of 1656 inhabitants and demonstrated a high prevalence of Chagas' infection (47.3%) and a high rate of Chagas' disease seropositivity among those with chronic myocardial heart disease (84.8%); heart disease was found in 17.3% of persons studied. The follow-up study was based on 812 persons and established that in the sample the frequency of Chagas' infection was 16.3% and that of heart disease 2.2%. Clinical, electrocardiographic and radiological analyses were made on patients with previous heart disease as well as on new patients. Different evolutive electrocardiographic patterns have been found, including variations ranging from normal to definitively abnormal. ImagesFIG. 1FIG. 2 PMID:4974002

  5. Oral transmission of Chagas disease by consumption of açaí palm fruit, Brazil.

    PubMed

    Nóbrega, Aglaêr A; Garcia, Marcio H; Tatto, Erica; Obara, Marcos T; Costa, Elenild; Sobel, Jeremy; Araujo, Wildo N

    2009-04-01

    In 2006, a total of 178 cases of acute Chagas disease were reported from the Amazonian state of Pará, Brazil. Eleven occurred in Barcarena and were confirmed by visualization of parasites on blood smears. Using cohort and case-control studies, we implicated oral transmission by consumption of açaí palm fruit.

  6. Chagas Disease in 2 Geriatric Rhesus Macaques (Macaca mulatta) Housed in the Pacific Northwest

    PubMed Central

    Dickerson, Mary F; Astorga, Nestor Gerardo; Astorga, Nestor Rodrigo; Lewis, Anne D

    2014-01-01

    Chagas disease (American trypanosomiasis) is caused by the protozoan parasite Trypanosoma cruzi. It is endemic in Latin America but also is found in the southern United States, particularly Texas and along the Gulf Coast. Typical clinical manifestations of Chagas disease are not well-characterized in rhesus macaques, but conduction abnormalities, myocarditis, and encephalitis and megaesophagus have been described. Here we report 2 cases of Chagas disease in rhesus macaques housed in the northwestern United States. The first case involved a geriatric male macaque with cardiomegaly, diagnosed as dilated cardiomyopathy on ultrasonographic examination. Postmortem findings included myocarditis as well as ganglioneuritis in the esophagus, stomach, and colon. The second case affected a geriatric female macaque experimentally infected with SIV. She was euthanized for a protocol-related time point. Microscopic examination revealed chronic myocarditis with amastigotes present in the cardiomyocytes, ganglioneuritis, and opportunistic infections attributed to her immunocompromised status. Banked serum samples from both macaques had positive titers for T. cruzi. T. cruzi DNA was amplified by conventional PCR from multiple tissues from both animals. Review of their histories revealed that both animals had been obtained from facilities in South Texas more than 12 y earlier. Given the long period of clinical latency, Chagas disease may be more prevalent in rhesus macaques than typically has been reported. T. cruzi infection should be considered for animals with unexplained cardiac or gastrointestinal pathology and that originated from areas known to have a high risk for disease transmission. PMID:25296019

  7. On the possibility of autochthonous Chagas disease in Roraima, Amazon region, Brazil, 2000-2001.

    PubMed

    Luitgards-Moura, José Francisco; Borges-Pereira, José; Costa, Jane; Zauza, Patrícia Lago; Rosa-Freitas, Maria Goreti

    2005-01-01

    Chagas disease has been almost entirely eradicated from the arid zones in Central and Northeastern Brazil where rare or no autochthonous cases have been reported. However, in the last 10 years the disease has increasingly been registered in the Amazon Region. Aiming to investigate the possibility of the occurrence of autochthonous cycle of Chagas disease in Roraima, triatomine collections, vectorial susceptibility studies (this one to be shown elsewhere), parasitological and serological analyses were conducted in three agricultural settlement areas (Rorainópolis, Passarão Project and Ilha Community). Blood-donor candidates were also investigated. This is the first epidemiological survey on Chagas disease conducted in agricultural settlements in Roraima. Triatomine species found were Triatoma maculata, Rhodnius pictipes, Rhodnius robustus and Panstrongylus geniculatus. Trypanosoma cruzi detection analyses included xenodiagnosis, indirect immunofluorescence, indirect hemaglutination, ELISA and kinetoplast PCR amplification. Natural triatomine infection was not found in intestinal contents. Twenty-five adult settlers (1.4% out of 1821, all > 15 year-old, 20 migrants) presented anti-T. cruzi antibodies. Two migrant settlers (from Minas Gerais and Maranhão) tested positive for more than two serological tests, besides either being positive for xenodiagnosis or PCR. Results show that Chagas disease is not endemic in the areas studied. However, all elements of the transmission cycle are present, demanding for an adequate and continuous vigilance.

  8. Science, health and development: Chagas disease in Brazil, 1943-1962.

    PubMed

    Kropf, S Petraglia

    2005-12-01

    The present paper discusses the historical construction and legitimacy of Chagas disease as a distinct nosological entity and as a public health issue in Brazil. It focuses on the activities of a group of researchers from Oswaldo Cruz Institute who worked at the Centre for the Study and Prevention of Chagas disease, located in Bambuí, Minas Gerais. Led in the 1940s and 50s by Emmanuel Dias, disciple of Carlos Chagas, the group made important contributions to the clinical characterization of Chagas disease as a cardiac illness, established the fact that it was technically possible to control the disease by using residual insecticides, and engaged in intense political mobilization to have the disease included as part of the Health Ministry sanitation campaigns. My hypothesis is that the group's work was a determining factor in the overcoming of certain unresolved controversies that had surrounded the medical and social identity of the disease since the 1920s. I examine to what extent this process was directly linked both to post-war optimism over new possibilities of combating infectious diseases and to the national and international debate on the relation between health and economic and social development.

  9. PREVALENCE OF CHAGAS DISEASE AMONG BLOOD DONOR CANDIDATES IN TRIANGULO MINEIRO, MINAS GERAIS STATE, BRAZIL.

    PubMed

    Lopes, Patrícia da Silva; Ramos, Eliezer Lucas Pires; Gómez-Hernández, César; Ferreira, Gabriela Lícia Santos; Rezende-Oliveira, Karine

    2015-12-01

    Despite public health campaigns and epidemiological surveillance activities, Chagas disease remains a major health problem in Latin America. According to data from the World Health Organization, there are approximately 7-8 million people infected with Trypanosoma cruzi worldwide, a large percentage of which in Latin America. This study aims to examine the serological profile of blood donors in blood banks of Hemominas hematology center, in the town of Ituiutaba, Minas Gerais State, Brazil. The study sample consisted of 53,941 blood donors, which were grouped according to gender and age. Sample collections were performed from January 1991 to December 2011, and 277 donors (0.5%) were considered serologically ineligible due to Chagas disease. Analysis of data showed no significant difference between genders. As for age, the highest proportion of ineligible donors was from 40 to 49 years (30%), and there was a positive correlation between increasing age and the percentage of patients seropositive for Chagas disease. Therefore, adopting strategies that allow the safe identification of donors with positive serology for Chagas disease is essential to reduce or eliminate indeterminate serological results.

  10. Investigation of the role of IL17A gene variants in Chagas disease.

    PubMed

    Leon Rodriguez, D A; Echeverría, L E; González, C I; Martin, J

    2015-12-01

    Human host genetic factors have been suggested to be determinants of the prevalence and clinical forms of Chagas disease. In this regard, IL-17A is believed to control parasitemia and protect against heart disease. In this work, we assessed whether IL17A gene polymorphisms are related to infection and/or development of the cardiac form of Chagas disease by genotyping for five IL17A SNPs (rs4711998, rs8193036, rs3819024, rs2275913 and rs7747909) in 1171 individuals from a Colombian region endemic for Chagas disease, classified as seronegative (n=595), seropositive asymptomatic (n=175) and chronic Chagas cardiomyopathy (n=401). Our results showed that SNP rs8193036, which is located upstream of the coding region of the gene, was slightly associated with protection against T. cruzi infection (P=0.0170, P(FDR)=0.0851, odds ratio (OR)=0.80, confidence interval (CI)=0.66-0.96) and associated with protection against the development of cardiomyopathy (P=0.0065, P(FDR)=0.0324, OR=0.75, CI=0.60-0.92). This finding suggests that this IL17A polymorphism could be associated with Trypanosoma cruzi infection and the development of chronic cardiomyopathy due to differential expression of cytokine IL-17A.

  11. ADENOSINE DEAMINASE ACTIVITY AND SERUM C-REACTIVE PROTEIN AS PROGNOSTIC MARKERS OF CHAGAS DISEASE SEVERITY.

    PubMed

    Bravo-Tobar, Iván Darío; Nello-Pérez, Carlota; Fernández, Alí; Mogollón, Nora; Pérez, Mary Carmen; Verde, Juan; Concepción, Juan Luis; Rodriguez-Bonfante, Claudina; Bonfante-Cabarcas, Rafael

    2015-01-01

    Chagas disease is a public health problem worldwide. The availability of diagnostic tools to predict the development of chronic Chagas cardiomyopathy is crucial to reduce morbidity and mortality. Here we analyze the prognostic value of adenosine deaminase serum activity (ADA) and C-reactive protein serum levels (CRP) in chagasic individuals. One hundred and ten individuals, 28 healthy and 82 chagasic patients were divided according to disease severity in phase I (n = 35), II (n = 29), and III (n = 18). A complete medical history, 12-lead electrocardiogram, chest X-ray, and M-mode echocardiogram were performed on each individual. Diagnosis of Chagas disease was confirmed by ELISA and MABA using recombinant antigens; ADA was determined spectrophotometrically and CRP by ELISA. The results have shown that CRP and ADA increased linearly in relation to disease phase, CRP being significantly higher in phase III and ADA at all phases. Also, CRP and ADA were positively correlated with echocardiographic parameters of cardiac remodeling and with electrocardiographic abnormalities, and negatively with ejection fraction. CRP and ADA were higher in patients with cardiothoracic index ≥ 50%, while ADA was higher in patients with ventricular repolarization disturbances. Finally, CRP was positively correlated with ADA. In conclusion, ADA and CRP are prognostic markers of cardiac dysfunction and remodeling in Chagas disease.

  12. Dynamics of the antibody-T.cruzi competition during Chagas infection: Prognostic relevance of intracellular replication

    NASA Astrophysics Data System (ADS)

    Sibona, G. J.; Condat, C. A.; Isasi, S. Cossy

    2005-02-01

    A recently proposed model for the competitive parasite-antibody interactions in Chagas disease is extended by separately describing the parasitic intracellular and extracellular phases. The model solutions faithfully reproduce available population data and yield predictions for parasite-induced cardiac cell damage.

  13. Interleukin-10 and tumour necrosis factor-alpha serum levels in chronic Chagas disease patients.

    PubMed

    Vasconcelos, R H T; Azevedo, E de A N; Diniz, G T N; Cavalcanti, M da G A de M; de Oliveira, W; de Morais, C N L; Gomes, Y de M

    2015-07-01

    In Chagas disease, chronically infected individuals may be asymptomatic or may present cardiac or digestive complications, and it is well known that the human immune response is related to different clinical manifestations. Different patterns of cytokine levels have been previously described in different clinical forms of this disease, but contradictory results are reported. Our aim was to evaluate the serum levels of interleukin-10 and tumour necrosis factor-alpha in patients with asymptomatic and cardiac Chagas disease. The serum interleukin-10 levels in patients with cardiomyopathy were higher than those in asymptomatic patients, mainly in those without heart enlargement. Although no significant difference was observed in serum tumour necrosis factor-alpha levels among the patients, we found that cardiac patients also present high levels of this cytokine, largely those with heart dilatation. Therefore, these cytokines play an important role in chronic Chagas disease cardiomyopathy. Follow-up investigations of these and other cytokines in patients with chronic Chagas disease need to be conducted to improve the understanding of the immunopathology of this disease.

  14. PREVALENCE OF CHAGAS DISEASE AMONG BLOOD DONOR CANDIDATES IN TRIANGULO MINEIRO, MINAS GERAIS STATE, BRAZIL.

    PubMed

    Lopes, Patrícia da Silva; Ramos, Eliezer Lucas Pires; Gómez-Hernández, César; Ferreira, Gabriela Lícia Santos; Rezende-Oliveira, Karine

    2015-12-01

    Despite public health campaigns and epidemiological surveillance activities, Chagas disease remains a major health problem in Latin America. According to data from the World Health Organization, there are approximately 7-8 million people infected with Trypanosoma cruzi worldwide, a large percentage of which in Latin America. This study aims to examine the serological profile of blood donors in blood banks of Hemominas hematology center, in the town of Ituiutaba, Minas Gerais State, Brazil. The study sample consisted of 53,941 blood donors, which were grouped according to gender and age. Sample collections were performed from January 1991 to December 2011, and 277 donors (0.5%) were considered serologically ineligible due to Chagas disease. Analysis of data showed no significant difference between genders. As for age, the highest proportion of ineligible donors was from 40 to 49 years (30%), and there was a positive correlation between increasing age and the percentage of patients seropositive for Chagas disease. Therefore, adopting strategies that allow the safe identification of donors with positive serology for Chagas disease is essential to reduce or eliminate indeterminate serological results. PMID:27049698

  15. PREVALENCE OF CHAGAS DISEASE AMONG BLOOD DONOR CANDIDATES IN TRIANGULO MINEIRO, MINAS GERAIS STATE, BRAZIL

    PubMed Central

    LOPES, Patrícia da Silva; RAMOS, Eliezer Lucas Pires; GÓMEZ-HERNÁNDEZ, César; FERREIRA, Gabriela Lícia Santos; REZENDE-OLIVEIRA, Karine

    2015-01-01

    Despite public health campaigns and epidemiological surveillance activities, Chagas disease remains a major health problem in Latin America. According to data from the World Health Organization, there are approximately 7-8 million people infected with Trypanosoma cruzi worldwide, a large percentage of which in Latin America. This study aims to examine the serological profile of blood donors in blood banks of Hemominas hematology center, in the town of Ituiutaba, Minas Gerais State, Brazil. The study sample consisted of 53,941 blood donors, which were grouped according to gender and age. Sample collections were performed from January 1991 to December 2011, and 277 donors (0.5%) were considered serologically ineligible due to Chagas disease. Analysis of data showed no significant difference between genders. As for age, the highest proportion of ineligible donors was from 40 to 49 years (30%), and there was a positive correlation between increasing age and the percentage of patients seropositive for Chagas disease. Therefore, adopting strategies that allow the safe identification of donors with positive serology for Chagas disease is essential to reduce or eliminate indeterminate serological results. PMID:27049698

  16. ADENOSINE DEAMINASE ACTIVITY AND SERUM C-REACTIVE PROTEIN AS PROGNOSTIC MARKERS OF CHAGAS DISEASE SEVERITY

    PubMed Central

    BRAVO-TOBAR, Iván Darío; NELLO-PÉREZ, Carlota; FERNÁNDEZ, Alí; MOGOLLÓN, Nora; PÉREZ, Mary Carmen; VERDE, Juan; CONCEPCIÓN, Juan Luis; RODRIGUEZ-BONFANTE, Claudina; BONFANTE-CABARCAS, Rafael

    2015-01-01

    SUMMARY Chagas disease is a public health problem worldwide. The availability of diagnostic tools to predict the development of chronic Chagas cardiomyopathy is crucial to reduce morbidity and mortality. Here we analyze the prognostic value of adenosine deaminase serum activity (ADA) and C-reactive protein serum levels (CRP) in chagasic individuals. One hundred and ten individuals, 28 healthy and 82 chagasic patients were divided according to disease severity in phase I (n = 35), II (n = 29), and III (n = 18). A complete medical history, 12-lead electrocardiogram, chest X-ray, and M-mode echocardiogram were performed on each individual. Diagnosis of Chagas disease was confirmed by ELISA and MABA using recombinant antigens; ADA was determined spectrophotometrically and CRP by ELISA. The results have shown that CRP and ADA increased linearly in relation to disease phase, CRP being significantly higher in phase III and ADA at all phases. Also, CRP and ADA were positively correlated with echocardiographic parameters of cardiac remodeling and with electrocardiographic abnormalities, and negatively with ejection fraction. CRP and ADA were higher in patients with cardiothoracic index ≥ 50%, while ADA was higher in patients with ventricular repolarization disturbances. Finally, CRP was positively correlated with ADA. In conclusion, ADA and CRP are prognostic markers of cardiac dysfunction and remodeling in Chagas disease. PMID:26603224

  17. Modeling Chagas Disease at Population Level to Explain Venezuela's Real Data

    PubMed Central

    González-Parra, Gilberto; Chen-Charpentier, Benito M.; Bermúdez, Moises

    2015-01-01

    Objectives In this paper we present an age-structured epidemiological model for Chagas disease. This model includes the interactions between human and vector populations that transmit Chagas disease. Methods The human population is divided into age groups since the proportion of infected individuals in this population changes with age as shown by real prevalence data. Moreover, the age-structured model allows more accurate information regarding the prevalence, which can help to design more specific control programs. We apply this proposed model to data from the country of Venezuela for two periods, 1961–1971, and 1961–1991 taking into account real demographic data for these periods. Results Numerical computer simulations are presented to show the suitability of the age-structured model to explain the real data regarding prevalence of Chagas disease in each of the age groups. In addition, a numerical simulation varying the death rate of the vector is done to illustrate prevention and control strategies against Chagas disease. Conclusion The proposed model can be used to determine the effect of control strategies in different age groups. PMID:26929912

  18. Chagas' disease and the use of implantable cardioverter-defibrillators in Brazil.

    PubMed

    Rosa, Ronaldo F; Neto, Argemiro S; Franken, Roberto A

    2006-01-01

    The authors discuss the epidemiology and pathogenesis of Chagas' disease in Brazil, including the use of treatment with a cardioverter-defibrillator in patients with low ejection fraction. Select patients may benefit from resynchronization therapy associated with cardioverter-defibrillator treatment. Electrophysiologic study is indicated in the assessment of the potential utility of an implantable cardioverter-defibrillator. PMID:17086031

  19. Metallothionein-1 and nitric oxide expression are inversely correlated in a murine model of Chagas disease.

    PubMed

    Gonzalez-Mejia, Martha Elba; Torres-Rasgado, Enrique; Porchia, Leonardo M; Salgado, Hilda Rosas; Totolhua, José-Luis; Ortega, Arturo; Hernández-Kelly, Luisa Clara Regina; Ruiz-Vivanco, Guadalupe; Báez-Duarte, Blanca G; Pérez-Fuentes, Ricardo

    2014-04-01

    Chagas disease, caused by Trypanosoma cruzi, represents an endemic among Latin America countries. The participation of free radicals, especially nitric oxide (NO), has been demonstrated in the pathophysiology of seropositive individuals with T. cruzi. In Chagas disease, increased NO contributes to the development of cardiomyopathy and megacolon. Metallothioneins (MTs) are efficient free radicals scavengers of NO in vitro and in vivo. Here, we developed a murine model of the chronic phase of Chagas disease using endemic T. cruzi RyCH1 in BALB/c mice, which were divided into four groups: infected non-treated (Inf), infected N-monomethyl-L-arginine treated (Inf L-NAME), non-infected L-NAME treated and non-infected vehicle-treated. We determined blood parasitaemia and NO levels, the extent of parasite nests in tissues and liver MT-I expression levels. It was observed that NO levels were increasing in Inf mice in a time-dependent manner. Inf L-NAME mice had fewer T. cruzi nests in cardiac and skeletal muscle with decreased blood NO levels at day 135 post infection. This affect was negatively correlated with an increase of MT-I expression (r = -0.8462, p < 0.0001). In conclusion, we determined that in Chagas disease, an unknown inhibitory mechanism reduces MT-I expression, allowing augmented NO levels.

  20. Accelerating the development of a therapeutic vaccine for human Chagas disease: rationale and prospects

    PubMed Central

    Zhan, Bin; Heffernan, Michael J; Jones, Kathryn; Valenzuela, Jesus G; Kamhawi, Shaden; Ortega, Jaime; de Leon Rosales, Samuel Ponce; Lee, Bruce Y; Bacon, Kristina M; Fleischer, Bernhard; Slingsby, BT; Cravioto, Miguel Betancourt; Tapia-Conyer, Roberto

    2013-01-01

    Chagas disease is a leading cause of heart disease affecting approximately 10 million people in Latin America and elsewhere worldwide. The two major drugs available for the treatment of Chagas disease have limited efficacy in Trypanosoma cruzi-infected adults with indeterminate (patients who have seroconverted but do not yet show signs or symptoms) and determinate (patients who have both seroconverted and have clinical disease) status; they require prolonged treatment courses and are poorly tolerated and expensive. As an alternative to chemotherapy, an injectable therapeutic Chagas disease vaccine is under development to prevent or delay Chagasic cardiomyopathy in patients with indeterminate or determinate status. The bivalent vaccine will be comprised of two recombinant T. cruzi antigens, Tc24 and TSA-1, formulated on alum together with the Toll-like receptor 4 agonist, E6020. Proof-of-concept for the efficacy of these antigens was obtained in preclinical testing at the Autonomous University of Yucatan. Here the authors discuss the potential for a therapeutic Chagas vaccine as well as the progress made towards such a vaccine, and the authors articulate a roadmap for the development of the vaccine as planned by the nonprofit Sabin Vaccine Institute Product Development Partnership and Texas Children’s Hospital Center for Vaccine Development in collaboration with an international consortium of academic and industrial partners in Mexico, Germany, Japan, and the USA. PMID:23151163

  1. Integrated control of Chagas disease for its elimination as public health problem--a review.

    PubMed

    Sosa-Estani, Sergio; Segura, Elsa Leonor

    2015-05-01

    Chagas disease or American trypanosomiasis is, together with geohelminths, the neglected disease that causes more loss of years of healthy life due to disability in Latin America. Chagas disease, as determined by the factors and determinants, shows that different contexts require different actions, preventing new cases or reducing the burden of disease. Control strategies must combine two general courses of action including prevention of transmission to prevent the occurrence of new cases (these measures are cost effective), as well as opportune diagnosis and treatment of infected individuals in order to prevent the clinical evolution of the disease and to allow them to recuperate their health. All actions should be implemented as fully as possible and with an integrated way, to maximise the impact. Chagas disease cannot be eradicated due because of the demonstrated existence of infected wild triatomines in permanent contact with domestic cycles and it contributes to the occurrence of at least few new cases. However, it is possible to interrupt the transmission of Trypanosoma cruzi in a large territory and to eliminate Chagas disease as a public health problem with a dramatic reduction of burden of the disease. PMID:25993503

  2. The endless race between Trypanosoma cruzi and host immunity: lessons for and beyond Chagas disease.

    PubMed

    Junqueira, Caroline; Caetano, Braulia; Bartholomeu, Daniella C; Melo, Mariane B; Ropert, Catherine; Rodrigues, Maurício M; Gazzinelli, Ricardo T

    2010-09-15

    Infection with the protozoan parasite Trypanosoma cruzi, the agent of Chagas disease, is characterised by a variable clinical course - from symptomless cases to severe chronic disease with cardiac and/or gastrointestinal involvement. The variability in disease outcome has been attributed to host responses as well as parasite heterogeneity. In this article, we review studies indicating the importance of immune responses as key determinants of host resistance to T. cruzi infection and the pathogenesis of Chagas disease. Particular attention is given to recent studies defining the role of cognate innate immune receptors and immunodominant CD8+ T cells that recognise parasite components - both crucial for host-parasite interaction and disease outcome. In light of these studies we speculate about parasite strategies that induce a strong and long-lasting T-cell-mediated immunity but at the same time allow persistence of the parasite in the vertebrate host. We also discuss what we have learned from these studies for increasing our understanding of Chagas pathogenesis and for the design of new strategies to prevent the development of Chagas disease. Finally, we highlight recent studies employing a genetically engineered attenuated T. cruzi strain as a vaccine shuttle that elicits potent T cell responses specific to a tumour antigen and protective immunity against a syngeneic melanoma cell line.

  3. Integrated control of Chagas disease for its elimination as public health problem - A Review

    PubMed Central

    Sosa-Estani, Sergio; Segura, Elsa Leonor

    2015-01-01

    Chagas disease or American trypanosomiasis is, together with geohelminths, the neglected disease that causes more loss of years of healthy life due to disability in Latin America. Chagas disease, as determined by the factors and determinants, shows that different contexts require different actions, preventing new cases or reducing the burden of disease. Control strategies must combine two general courses of action including prevention of transmission to prevent the occurrence of new cases (these measures are cost effective), as well as opportune diagnosis and treatment of infected individuals in order to prevent the clinical evolution of the disease and to allow them to recuperate their health. All actions should be implemented as fully as possible and with an integrated way, to maximise the impact. Chagas disease cannot be eradicated due because of the demonstrated existence of infected wild triatomines in permanent contact with domestic cycles and it contributes to the occurrence of at least few new cases. However, it is possible to interrupt the transmission of Trypanosoma cruzi in a large territory and to eliminate Chagas disease as a public health problem with a dramatic reduction of burden of the disease. PMID:25993503

  4. Integrated control of Chagas disease for its elimination as public health problem--a review.

    PubMed

    Sosa-Estani, Sergio; Segura, Elsa Leonor

    2015-05-01

    Chagas disease or American trypanosomiasis is, together with geohelminths, the neglected disease that causes more loss of years of healthy life due to disability in Latin America. Chagas disease, as determined by the factors and determinants, shows that different contexts require different actions, preventing new cases or reducing the burden of disease. Control strategies must combine two general courses of action including prevention of transmission to prevent the occurrence of new cases (these measures are cost effective), as well as opportune diagnosis and treatment of infected individuals in order to prevent the clinical evolution of the disease and to allow them to recuperate their health. All actions should be implemented as fully as possible and with an integrated way, to maximise the impact. Chagas disease cannot be eradicated due because of the demonstrated existence of infected wild triatomines in permanent contact with domestic cycles and it contributes to the occurrence of at least few new cases. However, it is possible to interrupt the transmission of Trypanosoma cruzi in a large territory and to eliminate Chagas disease as a public health problem with a dramatic reduction of burden of the disease.

  5. Update on oral Chagas disease outbreaks in Venezuela: epidemiological, clinical and diagnostic approaches.

    PubMed

    Noya, Belkisyolé Alarcón de; Díaz-Bello, Zoraida; Colmenares, Cecilia; Ruiz-Guevara, Raiza; Mauriello, Luciano; Muñoz-Calderón, Arturo; Noya, Oscar

    2015-05-01

    Orally transmitted Chagas disease has become a matter of concern due to outbreaks reported in four Latin American countries. Although several mechanisms for orally transmitted Chagas disease transmission have been proposed, food and beverages contaminated with whole infected triatomines or their faeces, which contain metacyclic trypomastigotes of Trypanosoma cruzi, seems to be the primary vehicle. In 2007, the first recognised outbreak of orally transmitted Chagas disease occurred in Venezuela and largest recorded outbreak at that time. Since then, 10 outbreaks (four in Caracas) with 249 cases (73.5% children) and 4% mortality have occurred. The absence of contact with the vector and of traditional cutaneous and Romana's signs, together with a florid spectrum of clinical manifestations during the acute phase, confuse the diagnosis of orally transmitted Chagas disease with other infectious diseases. The simultaneous detection of IgG and IgM by ELISA and the search for parasites in all individuals at risk have been valuable diagnostic tools for detecting acute cases. Follow-up studies regarding the microepidemics primarily affecting children has resulted in 70% infection persistence six years after anti-parasitic treatment. Panstrongylus geniculatus has been the incriminating vector in most cases. As a food-borne disease, this entity requires epidemiological, clinical, diagnostic and therapeutic approaches that differ from those approaches used for traditional direct or cutaneous vector transmission.

  6. Triatoma sanguisuga Blood Meals and Potential for Chagas Disease, Louisiana, USA

    PubMed Central

    Suarez, Julianne; Richards, Bethany; Dorn, Patricia L.

    2014-01-01

    To evaluate human risk for Chagas disease, we molecularly identified blood meal sources and prevalence of Trypanosoma cruzi infection among 49 Triatoma sanguisuga kissing bugs in Louisiana, USA. Humans accounted for the second most frequent blood source. Of the bugs that fed on humans, ≈40% were infected with T. cruzi, revealing transmission potential. PMID:25418456

  7. Behavioural alterations are independent of sickness behaviour in chronic experimental Chagas disease

    PubMed Central

    Vilar-Pereira, Glaucia; Ruivo, Leonardo Alexandre de Souza; Lannes-Vieira, Joseli

    2015-01-01

    The existence of the nervous form of Chagas disease is a matter of discussion since Carlos Chagas described neurological disorders, learning and behavioural alterations in Trypanosoma cruzi-infected individuals. In most patients, the clinical manifestations of the acute phase, including neurological abnormalities, resolve spontaneously without apparent consequence in the chronic phase of infection. However, chronic Chagas disease patients have behavioural changes such as psychomotor alterations, attention and memory deficits, and depression. In the present study, we tested whether or not behavioural alterations are reproducible in experimental models. We show that C57BL/6 mice chronically infected with the Colombian strain of T. cruzi (150 days post-infection) exhibit behavioural changes as (i) depression in the tail suspension and forced swim tests, (ii) anxiety analysed by elevated plus maze and open field test sand and (iii) motor coordination in the rotarod test. These alterations are neither associated with neuromuscular disorders assessed by the grip strength test nor with sickness behaviour analysed by temperature variation sand weight loss. Therefore, chronically T. cruzi-infected mice replicate behavioural alterations (depression and anxiety) detected in Chagas disease patients opening an opportunity to study the interconnection and the physiopathology of these two biological processes in an infectious scenario. PMID:26676323

  8. Behavioural alterations are independent of sickness behaviour in chronic experimental Chagas disease.

    PubMed

    Vilar-Pereira, Glaucia; Ruivo, Leonardo Alexandre de Souza; Lannes-Vieira, Joseli

    2015-12-01

    The existence of the nervous form of Chagas disease is a matter of discussion since Carlos Chagas described neurological disorders, learning and behavioural alterations in Trypanosoma cruzi-infected individuals. In most patients, the clinical manifestations of the acute phase, including neurological abnormalities, resolve spontaneously without apparent consequence in the chronic phase of infection. However, chronic Chagas disease patients have behavioural changes such as psychomotor alterations, attention and memory deficits, and depression. In the present study, we tested whether or not behavioural alterations are reproducible in experimental models. We show that C57BL/6 mice chronically infected with the Colombian strain of T. cruzi (150 days post-infection) exhibit behavioural changes as (i) depression in the tail suspension and forced swim tests, (ii) anxiety analysed by elevated plus maze and open field test sand and (iii) motor coordination in the rotarod test. These alterations are neither associated with neuromuscular disorders assessed by the grip strength test nor with sickness behaviour analysed by temperature variation sand weight loss. Therefore, chronically T. cruzi-infected mice replicate behavioural alterations (depression and anxiety) detected in Chagas disease patients opening an opportunity to study the interconnection and the physiopathology of these two biological processes in an infectious scenario. PMID:26676323

  9. Protection of vascular endothelium by aspirin in a murine model of chronic Chagas' disease.

    PubMed

    Molina-Berríos, Alfredo; Campos-Estrada, Carolina; Lapier, Michel; Duaso, Juan; Kemmerling, Ulrike; Galanti, Norbel; Ferreira, Jorge; Morello, Antonio; López-Muñoz, Rodrigo; Maya, Juan Diego

    2013-07-01

    Chronic Chagas' disease affects 10-30 % of patients infected with Trypanosoma cruzi, and it mainly manifests as cardiomyopathy. Important pathophysiological mechanisms involved in the cardiac lesions include activation of the endothelium and induced microvascular alterations. These processes involve the production of endothelial adhesion molecules and thromboxane A2, which are involved in inflammatory cell recruitment and platelet aggregation, respectively. Cyclooxygenase inhibitors such as aspirin decrease thromboxane production and alter the course of Chagas' disease, both in the acute and chronic phases. We studied the effects of the administration of low and high doses of aspirin during the early phase of T. cruzi infection, following microvascular damage in the context of a chronic murine model of Chagas' disease. The effects of both schedules were assessed at 24 and 90 days postinfection by evaluating parasitemia, mortality, and cardiac histopathological changes as well as the expression of ICAM, VCAM, and E-selectin in cardiac tissue. Thromboxane A2, soluble ICAM, and E-selectin blood levels were also measured. While aspirin did not affect parasitemia or mortality in the infected mice, it decreased both cardiac inflammatory infiltrates and thromboxane levels. Additionally, at 90 days postinfection, aspirin normalized sICAM and sE-selectin levels. Considering the improved endothelial function induced by aspirin, we propose the possibility of including this drug in clinical therapy to treat chronic Chagas' disease.

  10. Association of the Functional MICA-129 Polymorphism With the Severity of Chronic Chagas Heart Disease.

    PubMed

    Ayo, Christiane Maria; Oliveira, Amanda Priscila de; Camargo, Ana Vitória da Silveira; Mattos, Cinara Cássia Brandão de; Bestetti, Reinaldo Bulgarelli; Mattos, Luiz Carlos de

    2015-10-15

    MICA-129 polymorphism affects the binding affinity of MICA molecules with the NKG2D receptor and influences effector cell function. The genotype met/met was associated with the severity of left ventricular systolic dysfunction (LVSD) in patients with chronic Chagas heart disease, while the val/val genotype was associated with the absence of LVSD.

  11. Congenital Chagas' disease transmission in the United States: Diagnosis in adulthood.

    PubMed

    Murillo, Jorge; Bofill, Lina M; Bolivar, Hector; Torres-Viera, Carlos; Urbina, Julio A; Benhayon, Daniel; Torres, Jaime R

    2016-01-01

    Two brothers with congenitally-acquired Chagas' disease (CD) diagnosed during adulthood are reported. The patients were born in the USA to a mother from Bolivia who on subsequent assessment was found to be serologically positive for Trypanosoma cruzi. Serologic screening of all pregnant women who migrated from countries with endemic CD is strongly recommended. PMID:27516969

  12. Update on oral Chagas disease outbreaks in Venezuela: epidemiological, clinical and diagnostic approaches

    PubMed Central

    de Noya, Belkisyolé Alarcón; Díaz-Bello, Zoraida; Colmenares, Cecilia; Ruiz-Guevara, Raiza; Mauriello, Luciano; Muñoz-Calderón, Arturo; Noya, Oscar

    2015-01-01

    Orally transmitted Chagas disease has become a matter of concern due to outbreaks reported in four Latin American countries. Although several mechanisms for orally transmitted Chagas disease transmission have been proposed, food and beverages contaminated with whole infected triatomines or their faeces, which contain metacyclic trypomastigotes of Trypanosoma cruzi, seems to be the primary vehicle. In 2007, the first recognised outbreak of orally transmitted Chagas disease occurred in Venezuela and largest recorded outbreak at that time. Since then, 10 outbreaks (four in Caracas) with 249 cases (73.5% children) and 4% mortality have occurred. The absence of contact with the vector and of traditional cutaneous and Romana’s signs, together with a florid spectrum of clinical manifestations during the acute phase, confuse the diagnosis of orally transmitted Chagas disease with other infectious diseases. The simultaneous detection of IgG and IgM by ELISA and the search for parasites in all individuals at risk have been valuable diagnostic tools for detecting acute cases. Follow-up studies regarding the microepidemics primarily affecting children has resulted in 70% infection persistence six years after anti-parasitic treatment. Panstrongylus geniculatus has been the incriminating vector in most cases. As a food-borne disease, this entity requires epidemiological, clinical, diagnostic and therapeutic approaches that differ from those approaches used for traditional direct or cutaneous vector transmission. PMID:25946155

  13. Solar concentrator constructed with a circular prism array.

    PubMed

    Huang, Jia-hong; Fei, Wun-Ciang; Hsu, Wei-Chi; Tsai, Jui-che

    2010-08-10

    We present a novel idea to construct a solar concentrator with a circular prism array. FRED ray tracing software is used to evaluate our proposed structure in which the incident light rays are deflected by total internal reflection and the optical energy is concentrated and collected at the center. The light rays to be collected travel within the disk once they enter the module, saving the space that is reserved for ray propagation in other concentrators. Simulations for both single-wavelength and broadband light are performed. Our device can be used alone or serve as a secondary concentrator when combined with another solar-energy focusing module. For the proposed concentrator, an optical efficiency of 90% (single wavelength, 0.87 microm) is achieved under normal incidence and with antireflection coating, and a high geometric concentration ratio of 93 is reached. When combined with a Fresnel lens, which is used as a primary concentrator, the overall efficiency and concentration ratio can reach 92% (single wavelength, 0.87 microm) and 837, respectively.

  14. PRISM: A DATA-DRIVEN PLATFORM FOR MONITORING MENTAL HEALTH.

    PubMed

    Kamdar, Maulik R; Wu, Michelle J

    2016-01-01

    Neuropsychiatric disorders are the leading cause of disability worldwide and there is no gold standard currently available for the measurement of mental health. This issue is exacerbated by the fact that the information physicians use to diagnose these disorders is episodic and often subjective. Current methods to monitor mental health involve the use of subjective DSM-5 guidelines, and advances in EEG and video monitoring technologies have not been widely adopted due to invasiveness and inconvenience. Wearable technologies have surfaced as a ubiquitous and unobtrusive method for providing continuous, quantitative data about a patient. Here, we introduce PRISM-Passive, Real-time Information for Sensing Mental Health. This platform integrates motion, light and heart rate data from a smart watch application with user interactions and text entries from a web application. We have demonstrated a proof of concept by collecting preliminary data through a pilot study of 13 subjects. We have engineered appropriate features and applied both unsupervised and supervised learning to develop models that are predictive of user-reported ratings of their emotional state, demonstrating that the data has the potential to be useful for evaluating mental health. This platform could allow patients and clinicians to leverage continuous streams of passive data for early and accurate diagnosis as well as constant monitoring of patients suffering from mental disorders. PMID:26776198

  15. PRISM: A DATA-DRIVEN PLATFORM FOR MONITORING MENTAL HEALTH.

    PubMed

    Kamdar, Maulik R; Wu, Michelle J

    2016-01-01

    Neuropsychiatric disorders are the leading cause of disability worldwide and there is no gold standard currently available for the measurement of mental health. This issue is exacerbated by the fact that the information physicians use to diagnose these disorders is episodic and often subjective. Current methods to monitor mental health involve the use of subjective DSM-5 guidelines, and advances in EEG and video monitoring technologies have not been widely adopted due to invasiveness and inconvenience. Wearable technologies have surfaced as a ubiquitous and unobtrusive method for providing continuous, quantitative data about a patient. Here, we introduce PRISM-Passive, Real-time Information for Sensing Mental Health. This platform integrates motion, light and heart rate data from a smart watch application with user interactions and text entries from a web application. We have demonstrated a proof of concept by collecting preliminary data through a pilot study of 13 subjects. We have engineered appropriate features and applied both unsupervised and supervised learning to develop models that are predictive of user-reported ratings of their emotional state, demonstrating that the data has the potential to be useful for evaluating mental health. This platform could allow patients and clinicians to leverage continuous streams of passive data for early and accurate diagnosis as well as constant monitoring of patients suffering from mental disorders.

  16. PrismTech Data Distribution Service Java API Evaluation

    NASA Technical Reports Server (NTRS)

    Riggs, Cortney

    2008-01-01

    My internship duties with Launch Control Systems required me to start performance testing of an Object Management Group's (OMG) Data Distribution Service (DDS) specification implementation by PrismTech Limited through the Java programming language application programming interface (API). DDS is a networking middleware for Real-Time Data Distribution. The performance testing involves latency, redundant publishers, extended duration, redundant failover, and read performance. Time constraints allowed only for a data throughput test. I have designed the testing applications to perform all performance tests when time is allowed. Performance evaluation data such as megabits per second and central processing unit (CPU) time consumption were not easily attainable through the Java programming language; they required new methods and classes created in the test applications. Evaluation of this product showed the rate that data can be sent across the network. Performance rates are better on Linux platforms than AIX and Sun platforms. Compared to previous C++ programming language API, the performance evaluation also shows the language differences for the implementation. The Java API of the DDS has a lower throughput performance than the C++ API.

  17. Application of derivative matrices of skew rays to design of compound dispersion prisms.

    PubMed

    Lin, Psang Dain

    2016-09-01

    Numerous optimization methods have been developed in recent decades for optical system design. However, these methods rely heavily on ray tracing and finite difference techniques to estimate the derivative matrices of the rays. Consequently, the accuracy of the results obtained from these methods is critically dependent on the incremental step size used in the tuning stage. To overcome this limitation, the present study proposes a comprehensive methodology for the design of compound dispersion prisms based on the first- and second-order derivative matrices of skew rays. The proposed method facilitates the analysis and design of prisms with respect to arbitrary system variables and provides an ideal basis for automatic prism design applications. Four illustrative examples are given. It is shown that the optical quantities required to evaluate the prism performance can be extracted directly from the proposed derivative matrices. In addition, it is shown in this study that the single-element 3D prism can have the same deviation angle and spectral dispersion as the 2D compound prism. PMID:27607509

  18. Rhomboid prism pair for rotating the plane of parallel light beams

    NASA Technical Reports Server (NTRS)

    Orloff, K. L. (Inventor); Yanagita, H.

    1982-01-01

    An optical system is described for rotating the plane defined by a pair of parallel light beams. In one embodiment a single pair of rhomboid prisms have their respective input faces disposed to receive the respective input beams. Each prism is rotated about an axis of revolution coaxial with each of the respective input beams by means of a suitable motor and gear arrangement to cause the plane of the parallel output beams to be rotated relative to the plane of the input beams. In a second embodiment, two pairs of rhomboid prisms are provided. In a first angular orientation of the output beams, the prisms merely decrease the lateral displacement of the output beams in order to keep in the same plane as the input beams. In a second angular orientation of the prisms, the input faces of the second pair of prisms are brought into coincidence with the input beams for rotating the plane of the output beams by a substantial angle such as 90 deg.

  19. Optical system design of the Dyson imaging spectrometer based on the Fery prism

    NASA Astrophysics Data System (ADS)

    Pei, Linlin; Xiangli, Bin; Lv, Qunbo; Shao, Xiaopeng

    2016-08-01

    Imaging spectrometer has obtained wide development since rich feature information can be obtained by it; now, we focus on its high spectral resolution and miniaturization. In this paper, we design the Dyson imaging spectrometer system based on Fery prism. The average spectral resolution is 4.3 nm and the structure of the total length is 229 mm. It is a small, high-spectrometer imaging system. The front and rear surface of the traditional prism are plane, but the surfaces of the Fery prism are spherical, which can provide some optical power to realize imaging function and produce the dispersion effect. The Fery prism does not need to be placed in the parallel optical path, which simplifies the collimator lens and the imaging lens and are necessary in the prism spectrometer, making it possible to obtain a compact spectrometer. Full-spectrum transmittance of the prism is up to 94 %. Compared to the convex grating, the energy efficiency is greatly improved, and the free spectral range is wider, and its dispersion will not bring higher-order spectral aliasing problem. The small high spectrometer only includes two components. Its spectral range is from 400 to 1000 nm, covering the near-ultraviolet to near-infrared. The various aberrations of the typical spectrum are corrected. The spectrometer is excellent in performance.

  20. Modelling the differential effects of prisms on perception and action in neglect.

    PubMed

    Leigh, Steven; Danckert, James; Eliasmith, Chris

    2015-03-01

    Damage to the right parietal cortex often leads to a syndrome known as unilateral neglect in which the patient fails to attend or respond to stimuli in left space. Recent work attempting to rehabilitate the disorder has made use of rightward-shifting prisms that displace visual input further rightward. After a brief period of adaptation to prisms, many of the symptoms of neglect show improvements that can last for hours or longer, depending on the adaptation procedure. Recent work has shown, however, that differential effects of prisms can be observed on actions (which are typically improved) and perceptual biases (which often remain unchanged). Here, we present a computational model capable of explaining some basic symptoms of neglect (line bisection behaviour), the effects of prism adaptation in both healthy controls and neglect patients and the observed dissociation between action and perception following prisms. The results of our simulations support recent contentions that prisms primarily influence behaviours normally thought to be controlled by the dorsal stream.

  1. Application of derivative matrices of skew rays to design of compound dispersion prisms.

    PubMed

    Lin, Psang Dain

    2016-09-01

    Numerous optimization methods have been developed in recent decades for optical system design. However, these methods rely heavily on ray tracing and finite difference techniques to estimate the derivative matrices of the rays. Consequently, the accuracy of the results obtained from these methods is critically dependent on the incremental step size used in the tuning stage. To overcome this limitation, the present study proposes a comprehensive methodology for the design of compound dispersion prisms based on the first- and second-order derivative matrices of skew rays. The proposed method facilitates the analysis and design of prisms with respect to arbitrary system variables and provides an ideal basis for automatic prism design applications. Four illustrative examples are given. It is shown that the optical quantities required to evaluate the prism performance can be extracted directly from the proposed derivative matrices. In addition, it is shown in this study that the single-element 3D prism can have the same deviation angle and spectral dispersion as the 2D compound prism.

  2. Patients with homonymous hemianopia become visually qualified to drive using novel monocular sector prisms.

    PubMed

    Moss, Adam M; Harrison, Andrew R; Lee, Michael S

    2014-03-01

    Patients with homonymous hemianopia (HH) often fail to meet visual field (VF) requirements for a driver's license. We describe 2 patients with complete HH, who met the minimum VF requirements for driving using a novel, high-power, monocular sector prism system. Baseline VFs were assessed using automated and kinetic perimetry. Patients were fitted with glasses and press-on 57-PD peripheral monocular sector prisms placed on the lens ipsilateral to the VF defect above and below the visual axis with prisms oriented obliquely. Kinetic perimetry was reassessed both monocularly and binocularly, with and without prisms. The 2 patients had 95° and 82° angle of continuous, horizontal, binocular VF. With the use of the prism system, the binocular VF increased to 115° and 112° angles. Both patients reported improvement in quality of life and each holds a valid driver's license and has successfully operated a motor vehicle without any restrictions or accidents. These findings suggest that the addition of oblique 57-PD prisms to the ipsilateral spectacle lens above and below the visual axis for patients with complete HH can significantly increase horizontal VF, which may help an individual become visually qualified to obtain a driver's license.

  3. Asymmetrical effects of adaptation to left- and right-shifting prisms depends on pre-existing attentional biases.

    PubMed

    Goedert, Kelly M; Leblanc, Andrew; Tsai, Sen-Wei; Barrett, Anna M

    2010-09-01

    Proposals that adaptation with left-shifting prisms induces neglect-like symptoms in normal individuals rely on a dissociation between the postadaptation performance of individuals trained with left- versus right-shifting prisms (e.g., Colent, Pisella, & Rossetti, 2000). A potential problem with this evidence is that normal young adults have an a priori leftward bias (e.g., Jewell & McCourt, 2000). In Experiment 1, we compared the line bisection performance of young adults to that of aged adults, who as a group may lack a leftward bias in line bisection. Participants trained with both left- and right-shifting prisms. Consistent with our hypothesis, while young adults demonstrated aftereffects for left, but not right prisms, aged adults demonstrated reliable aftereffects for both prisms. In Experiment 2, we recruited a larger sample of young adults, some of whom were right-biased at baseline. We observed an interaction between baseline bias and prism-shift, consistent with the results of Experiment 1: Left-biased individuals showed a reduced aftereffect when training with right-shifting prisms and right-biased individuals showed a reduced aftereffect when training with left-shifting prisms. These results suggest that previous failures to find generalizable aftereffects with right-shifting prisms may be driven by participants' baseline biases rather than specific effects of the prism itself.

  4. [Investigation of vectors and reservoirs in an acute Chagas outbreak due to possible oral transmission in Aguachica, Cesar, Colombia].

    PubMed

    Soto, Hugo; Tibaduiza, Tania; Montilla, Marleny; Triana, Omar; Suárez, Diana Carolina; Torres Torres, Mariela; Arias, María Teresa; Lugo, Ligia

    2014-04-01

    Colombia recorded 11 cases of acute Chagas disease and 80 cases of oral contamination with Trypanosoma cruzi. The current study analyzes the entomological and parasitological characteristics of the outbreak in Aguachica, Cesar Department, in 2010. An interdisciplinary group of health professionals and regional university personnel conducted the laboratory tests in the patients and the investigation of the transmission focus. Eleven cases of acute Chagas diseases were detected in a single family in a dwelling with domiciliated triatomines and Rhodnius pallescens, Pantrongylus geniculatus, Eratyrus cuspidatus, and two Didelphis marsupialis opossums infected with T. cruzi in Attalea butyracea and Elaeis oleifera palm trees in the urban area of Aguachica. The study analyzes the role of R. pallescens and palm trees in the wild cycle of T. cruzi and in oral transmission of Chagas disease. Sporadic incursions by wild R. pallescens, P. geniculatus, and E. cuspidatus from the nearby palm trees into human dwellings may cause increasingly frequent outbreaks of oral Chagas disease.

  5. Planar scanning method for detecting refraction characteristics of two-dimensional photonic quasi-crystal wedge-shaped prisms.

    PubMed

    Liu, Jianjun; Tan, Wei; Liu, Exian; Hu, Haili; Fan, Zhigang; Zhang, Tianhua; Zhang, Xiong

    2016-05-01

    In this study, a planar scanning method is proposed. This novel method adapts two monitors moving along double planar tracks that can be used to detect refraction characteristics of two-dimensional (2D) photonic quasi-crystal (PQC) wedge-shaped prisms. Refraction of a decagonal Penrose-type PQC prism is analyzed for a given incident beam and two polarization modes at different incident positions in the prism using this method. Refraction from the prism is irregular, indicating that nonuniformity in the arrangement of scatterers in the prism causes Bragg-like scattering irregularities. Numerical results show that this method can be used for guiding the design of a 2D PQC prism and for the analysis of its refraction characteristics. PMID:27140896

  6. Planar scanning method for detecting refraction characteristics of two-dimensional photonic quasi-crystal wedge-shaped prisms.

    PubMed

    Liu, Jianjun; Tan, Wei; Liu, Exian; Hu, Haili; Fan, Zhigang; Zhang, Tianhua; Zhang, Xiong

    2016-05-01

    In this study, a planar scanning method is proposed. This novel method adapts two monitors moving along double planar tracks that can be used to detect refraction characteristics of two-dimensional (2D) photonic quasi-crystal (PQC) wedge-shaped prisms. Refraction of a decagonal Penrose-type PQC prism is analyzed for a given incident beam and two polarization modes at different incident positions in the prism using this method. Refraction from the prism is irregular, indicating that nonuniformity in the arrangement of scatterers in the prism causes Bragg-like scattering irregularities. Numerical results show that this method can be used for guiding the design of a 2D PQC prism and for the analysis of its refraction characteristics.

  7. Extended-Range Ultrarefractive 1D Photonic Crystal Prisms

    NASA Technical Reports Server (NTRS)

    Ting, David Z.

    2007-01-01

    by use of conventional prisms and diffraction gratings and is highly nonlinear.

  8. Prism Adaptation and Aftereffect: Specifying the Properties of a Procedural Memory System

    PubMed Central

    Fernández-Ruiz, Juan; Díaz, Rosalinda

    1999-01-01

    Prism adaptation, a form of procedural learning, is a phenomenon in which the motor system adapts to new visuospatial coordinates imposed by prisms that displace the visual field. Once the prisms are withdrawn, the degree and strength of the adaptation can be measured by the spatial deviation of the motor actions in the direction opposite to the visual displacement imposed by the prisms, a phenomenon known as aftereffect. This study was designed to define the variables that affect the acquisition and retention of the aftereffect. Subjects were required to throw balls to a target in front of them before, during, and after lateral displacement of the visual field with prismatic spectacles. The diopters of the prisms and the number of throws were varied among different groups of subjects. The results show that the adaptation process is dependent on the number of interactions between the visual and motor system, and not on the time spent wearing the prisms. The results also show that the magnitude of the aftereffect is highly correlated with the magnitude of the adaptation, regardless of the diopters of the prisms or the number of throws. Finally, the results suggest that persistence of the aftereffect depends on the number of throws after the adaptation is complete. On the basis of these results, we propose that the system underlying this kind of learning stores at least two different parameters, the contents (measured as the magnitude of displacement) and the persistence (measured as the number of throws to return to the baseline) of the learned information. PMID:10355523

  9. XeCl excimer laser with new prism resonator configurations and its performance characteristics.

    PubMed

    Benerji, N S; Singh, A; Varshnay, N; Singh, Bijendra

    2015-07-01

    New resonator cavity configurations, namely, the prism resonator and unstable prism resonator, are demonstrated for the first time in an excimer (XeCl) laser with interesting and novel results. High misalignment tolerance ∼50 mrad is achieved with considerably reduced beam divergence of less than ∼1 mrad without reduction in output power capabilities of the laser. The misalignment tolerance of ∼50 mrad is a dramatic improvement of ∼25 times compared to ∼2 mrad normally observed in standard excimer laser with plane-plane cavity. Increase in depth of focus from 3 mm to 5.5 mm was also achieved in case of prism resonator configuration with an improvement of about 60%. Unstable prism resonator configuration is demonstrated here in this paper with further reduction in beam divergence to about 0.5 mrad using plano-convex lens as output coupler. The misalignment tolerance in case of unstable prism resonator was retained at about 30 mrad which is a high value compared to standard unstable resonators. The output beam spot was completely filled with flat-top profile with prism resonator configurations, which is desired for various material processing applications. Focusing properties and beam divergence in case of prism resonator have been investigated using SEM (scanning electron microscope) images. SEM images of the focused spot size (∼20 μm holes) on metal sheet indicate beam divergence of about 0.05 mrad which is about 1.5 times diffraction limit. Energy contained in this angle is thus sufficient for micro-machining applications. Clean and sharp edges of the micro-holes show high pointing stability with multiple shot exposures. Such characteristics of the excimer laser system will be extremely useful in micro-machining and other field applications. PMID:26233361

  10. XeCl excimer laser with new prism resonator configurations and its performance characteristics

    SciTech Connect

    Benerji, N. S. E-mail: bsingh@rrcat.gov.in; Singh, A.; Varshnay, N.; Singh, Bijendra E-mail: bsingh@rrcat.gov.in

    2015-07-15

    New resonator cavity configurations, namely, the prism resonator and unstable prism resonator, are demonstrated for the first time in an excimer (XeCl) laser with interesting and novel results. High misalignment tolerance ∼50 mrad is achieved with considerably reduced beam divergence of less than ∼1 mrad without reduction in output power capabilities of the laser. The misalignment tolerance of ∼50 mrad is a dramatic improvement of ∼25 times compared to ∼2 mrad normally observed in standard excimer laser with plane-plane cavity. Increase in depth of focus from 3 mm to 5.5 mm was also achieved in case of prism resonator configuration with an improvement of about 60%. Unstable prism resonator configuration is demonstrated here in this paper with further reduction in beam divergence to about 0.5 mrad using plano-convex lens as output coupler. The misalignment tolerance in case of unstable prism resonator was retained at about 30 mrad which is a high value compared to standard unstable resonators. The output beam spot was completely filled with flat-top profile with prism resonator configurations, which is desired for various material processing applications. Focusing properties and beam divergence in case of prism resonator have been investigated using SEM (scanning electron microscope) images. SEM images of the focused spot size (∼20 μm holes) on metal sheet indicate beam divergence of about 0.05 mrad which is about 1.5 times diffraction limit. Energy contained in this angle is thus sufficient for micro-machining applications. Clean and sharp edges of the micro-holes show high pointing stability with multiple shot exposures. Such characteristics of the excimer laser system will be extremely useful in micro-machining and other field applications.

  11. Adaptation to leftward-shifting prisms reduces the global processing bias of healthy individuals.

    PubMed

    Bultitude, Janet H; Woods, Jill M

    2010-05-01

    When healthy individuals are presented with peripheral figures in which small letters are arranged to form a large letter, they are faster to identify the global- than the local-level information, and have difficulty ignoring global information when identifying the local level. The global reaction time (RT) advantage and global interference effect imply preferential processing of global-level information in the normal brain. This contrasts with the local processing bias demonstrated following lesions to the right temporo-parietal junction (TPJ), such as those that lead to hemispatial neglect (neglect). Recent research from our lab demonstrated that visuo-motor adaptation to rightward-shifting prisms, which ameliorates many leftward performance deficits of neglect patients, improved the local processing bias of patients with right TPJ lesions (Bultitude, Rafal, & List, 2009). Here we demonstrate that adaptation to leftward-shifting prisms, which can induce neglect-like performance in neurologically healthy individuals, also reduces the normal global processing bias. Forty-eight healthy participants were asked to identify the global or local forms of hierarchical figures before and after adaptation to leftward- or rightward-shifting prisms. Prior to prism adaptation, both groups had greater difficulty ignoring irrelevant global information when identifying the local level (global interference) compared to their ability to ignore irrelevant local-level information when identifying the global level (local interference). Participants who adapted to leftward-shifting prisms showed a significant reduction in global interference, but there was no change in the performance of the rightward-shifting Prism Group. These results show, for the first time, that in addition to previously demonstrated effects on lateralised attention, prism adaptation can influence non-lateralised spatial attention in healthy individuals.

  12. Synthesis of hexagonal wurtzite Cu2ZnSnS4 prisms by an ultrasound-assisted microwave solvothermal method

    NASA Astrophysics Data System (ADS)

    Long, Fei; Chi, Shangsen; He, Jinyun; Wang, Jilin; Wu, Xiaoli; Mo, Shuyi; Zou, Zhengguang

    2015-09-01

    Wurtzite Cu2ZnSnS4 (CZTS) hexagonal prisms were synthesized by a simple ultrasound-microwave solvothermal method. The product was characterized by XRD, FESEM, EDS, TEM, Raman and UV-vis spectrometer. The hexagonal prisms were 0.5-2 μm wide and 5-12 μm long. The PVP played an important role in the formation of the CZTS hexagonal prisms. In addition, the ultrasound-assisted microwave process was helpful for synthesis of wurtzite rather than kesterite phase CZTS. A nucleation-dissolution-recrystallization mechanism was also proposed to explain the growth of the CZTS hexagonal prisms.

  13. All-prism achromatic phase matching for tunable second-harmonic generation

    SciTech Connect

    Richman, Bruce A.; Bisson, Scott E.; Trebino, Rick; Jacobson, Alexander

    1999-05-01

    Achromatic phase matching (APM) involves dispersing the light entering a nonlinear optical crystal so that a wide range of wavelengths is simultaneously phase matched. We constructed an APM apparatus consisting of six prisms, the final dispersion angle of which was optimized to match to second order in wavelength the type I phase-matching angle of {beta} barium borate (BBO). With this apparatus, we doubled tunable fundamental light from 620 to 700 nm in wavelength using a 4-mm-long BBO crystal. An analogous set of six prisms after the BBO crystal, optimized to second order in second-harmonic wavelength, realigned the output second-harmonic beams. Computer simulations predict that adjustment of a single prism can compensate angular misalignment of any or all the prisms before the crystal, and similarly for the prisms after the crystal. We demonstrated such compensations with the experimental device. The simulations also indicate that the phase-matching wavelength band can be shifted and optimized for different crystal lengths. {copyright} 1999 Optical Society of America

  14. A conceptual design of PRISM-2 for Advanced Land Observing Satellite-3(ALOS-3)

    NASA Astrophysics Data System (ADS)

    Imai, Hiroko; Katayama, Haruyoshi; Sagisaka, Masakazu; Hatooka, Yasushi; Suzuki, Shinichi; Osawa, Yuji; Takahashi, Masuo; Tadono, Takeo

    2012-09-01

    The Japan Aerospace Exploration Agency (JAXA) is planning a satellite system including Advanced Land Observing Satellites 2 and 3 (ALOS-2 and ALOS-3) for the ALOS follow-on program. ALOS-3 will carry the optical sensor named "PRISM-2" and extend the capabilities of earlier ALOS missions. PRISM-2 will be able to collect high-resolution (0.8m) and wide-swath (50 km) imagery with high geo-location accuracy, as well as provide precise digital surface models (DSMs) using stereo pair images acquired by two telescopes. These capabilities are ideal for obtaining large-scale geographical information such as elevation and land cover-maps for use in many research areas and practical applications, including disaster management support. JAXA has conducted a phase A study of the ALOS-3 spacecraft and PRISM-2, and is now working on prototype models of key components of PRISM-2's telescope, focal plane, and data compressor. This paper introduces a conceptual design for PRISM-2 and the ALOS-3 system.

  15. Sufficient conditions for the avoidance of spectral dispersion in optical prisms.

    PubMed

    Lin, Psang Dain

    2016-07-01

    Prisms are common optical elements consisting of only flat boundary surfaces. Two conditions need to be fulfilled to avoid chromatic aberration for a prism, namely, no mutual image tilt and no mutual image shift for different wavelengths. Mutual image tilt occurs when the unit directional vector of the exit ray varies as a function of the prism's refractive index, resulting in spectral dispersion. In a previous study by the present group [Appl. Opt.45, 3951 (2006)APOPAI0003-693510.1364/AO.45.003951], it was shown that when the rays enter and exit a prism perpendicularly, image reorientation is achieved without spectral dispersion. The present study derives a further sufficient condition to avoid spectral dispersion caused by refraction. The condition explains the ability of Dove prisms and solid glass corner cubes to produce the required image orientation even when the entrance and exit rays are not normal to the respective boundary surfaces. In general, the proposed condition provides a useful analytical guideline for avoiding spectral dispersion in a wide variety of optical systems. PMID:27409681

  16. Investigation of beam steering performances in rotation Risley-prism scanner.

    PubMed

    Li, Anhu; Sun, Wansong; Yi, Wanli; Zuo, Qiyou

    2016-06-13

    Rotation Risley-prism scanner appears to be the most promising solution to high-accuracy beam scanning and target tracking. In the paper, some important issues crucial to the function implementation are thoroughly investigated. First the forming law of scan blind zone relative to double-prism structural parameters is explored by a quantitative analysis method. Then the nonlinear relationship between the rotation speeds of double prisms and the change rate of beam deviation angle is presented, and the beam scan singularity is indicated as an essential factor that confines the beam scan region. Finally, the high-accuracy radial scan theory is verified to illustrate the important application owing to the high reduction ratio from the rotation angles of double prisms to the deviation angles of the emergent beam. The research not only reveals the inner mechanisms of the Risley-prism beam scanning in principle, but also provide a foundation for the nonlinear control of various beam scan modes. PMID:27410303

  17. Spatial effects of shifting prisms on properties of posterior parietal cortex neurons

    PubMed Central

    Karkhanis, Anushree N; Heider, Barbara; Silva, Fabian Muñoz; Siegel, Ralph M

    2014-01-01

    The posterior parietal cortex contains neurons that respond to visual stimulation and motor behaviour. The objective of the current study was to test short-term adaptation in neurons in macaque area 7a and the dorsal prelunate during visually guided reaching using Fresnel prisms that displaced the visual field. The visual perturbation shifted the eye position and created a mismatch between perceived and actual reach location. Two non-human primates were trained to reach to visual targets before, during and after prism exposure while fixating the reach target in different locations. They were required to reach to the physical location of the reach target and not the perceived, displaced location. While behavioural adaptation to the prisms occurred within a few trials, the majority of neurons responded to the distortion either with substantial changes in spatial eye position tuning or changes in overall firing rate. These changes persisted even after prism removal. The spatial changes were not correlated with the direction of induced prism shift. The transformation of gain fields between conditions was estimated by calculating the translation and rotation in Euler angles. Rotations and translations of the horizontal and vertical spatial components occurred in a systematic manner for the population of neurons suggesting that the posterior parietal cortex retains a constant representation of the visual field remapping between experimental conditions. PMID:24928956

  18. THREE-DIMENSIONAL IGNITION AND GROWTH REACTIVE FLOW MODELING OF PRISM FAILURE TESTS ON PBX 9502

    SciTech Connect

    Garcia, M L; Tarver, C M

    2006-06-20

    The Ignition and Growth reactive flow model for shock initiation and detonation of solid explosives based on triaminotirnitrobenzene (TATB) is applied to three-dimensional detonation wave propagation. The most comprehensive set of three-dimensional detonation wave propagation data is that measured using the trapezoidal prism test. In this test, a PBX 9501 (95% HMX, 2.5% Estane, and 2.5% BDNPA/F) line detonator initiates a detonation wave along the trapezoidal face of a PBX 9502 (95% TATB and 5% Kel-F binder) prism. The failure thickness, which has been shown experimentally to be roughly half of the failure diameter of a long cylindrical charge, is measured after 50 mm of detonation wave propagation by impact with an aluminum witness plate. The effects of confinement impedance on the PBX 9502 failure thickness have been measured using air (unconfined), water, PMMA, magnesium, aluminum, lead, and copper placed in contact with the rectangular faces of the prism parallel to the direction of detonation propagation. These prism test results are modeled using the two-dimensional PBX 9502 Ignition and Growth model parameters determined by calculating failure diameter and tested on recent corner turning experiments. Good agreement between experimentally measured and calculated prism failure thicknesses for unconfined and confined PBX 9502 is reported.

  19. DSM Generation from ALSO/PRISM Images Using SAT-PP

    NASA Astrophysics Data System (ADS)

    Wolff, Kirsten; Gruen, Armin

    2008-11-01

    One of the most important products of ALOS/PRISM image data are accurate DSMs. To exploit the full potential of the full resolution of PRISM for DSM generation, a highly developed image matcher is needed. As a member of the validation and calibration team for PRISM we published earlier results of DSM generation using PRISM image triplets in combination with our software package SAT-PP. The overall accuracy across all object and image features for all tests lies between 1-5 pixels in matching, depending primarily on surface roughness, vegetation, image texture and image quality. Here we will discuss some new results. We focus on four different topics: the use of two different evaluation methods, the difference between a 5m and a 10m GSD for the final PRISM DSM, the influence of the level of initial information and the comparison of the quality of different combinations of the three different views forward, nadir and backward. All tests have been conducted with our testfield Bern/Thun, Switzerland.

  20. Affective three-dimensional brain-computer interface created using a prism array-based display

    NASA Astrophysics Data System (ADS)

    Mun, Sungchul; Park, Min-Chul

    2014-12-01

    To avoid the vergence-accommodation mismatch and provide a strong sense of presence to users, we applied a prism array-based display when presenting three-dimensional (3-D) objects. Emotional pictures were used as visual stimuli to increase the signal-to-noise ratios of steady-state visually evoked potentials (SSVEPs) because involuntarily motivated selective attention by affective mechanisms can enhance SSVEP amplitudes, thus producing increased interaction efficiency. Ten male and nine female participants voluntarily participated in our experiments. Participants were asked to control objects under three viewing conditions: two-dimension (2-D), stereoscopic 3-D, and prism. The participants performed each condition in a counter-balanced order. One-way repeated measures analysis of variance showed significant increases in the positive predictive values in the prism condition compared to the 2-D and 3-D conditions. Participants' subjective ratings of realness and engagement were also significantly greater in the prism condition than in the 2-D and 3-D conditions, while the ratings for visual fatigue were significantly reduced in the prism condition than in the 3-D condition. The proposed methods are expected to enhance the sense of reality in 3-D space without causing critical visual fatigue. In addition, people who are especially susceptible to stereoscopic 3-D may be able to use the affective brain-computer interface.

  1. Prism-patterned Nafion membrane for enhanced water transport in polymer electrolyte membrane fuel cell

    NASA Astrophysics Data System (ADS)

    Kim, Sang Moon; Kang, Yun Sik; Ahn, Chiyeong; Jang, Segeun; Kim, Minhyoung; Sung, Yung-Eun; Yoo, Sung Jong; Choi, Mansoo

    2016-06-01

    Here, we report a simple and effective strategy to enhance the performance of the polymer electrolyte membrane fuel cell by imprinting prism-patterned arrays onto the Nafion membrane, which provides three combined effects directly related to the device performance. First, a locally thinned membrane via imprinted micro prism-structures lead to reduced membrane resistance, which is confirmed by electrochemical impedance spectroscopy. Second, increments of the geometrical surface area of the prism-patterned Nafion membrane compared to a flat membrane result in the increase in the electrochemical active surface area. Third, the vertically asymmetric geometry of prism structures in the cathode catalyst layer lead to enhanced water transport, which is confirmed by oxygen gain calculation. To explain the enhanced water transport, we propose a simple theoretical model on removal of water droplets existing in the asymmetric catalyst layer. These three combined effects achieved via incorporating prism patterned arrays into the Nafion membrane effectively enhance the performance of the polymer electrolyte membrane fuel cell.

  2. All-prism achromatic phase matching for tunable second-harmonic generation.

    PubMed

    Richman, B A; Bisson, S E; Trebino, R; Sidick, E; Jacobson, A

    1999-05-20

    Achromatic phase matching (APM) involves dispersing the light entering a nonlinear optical crystal so that a wide range of wavelengths is simultaneously phase matched. We constructed an APM apparatus consisting of six prisms, the final dispersion angle of which was optimized to match to second order in wavelength the type I phase-matching angle of beta barium borate (BBO). With this apparatus, we doubled tunable fundamental light from 620 to 700 nm in wavelength using a 4-mm-long BBO crystal. An analogous set of six prisms after the BBO crystal, optimized to second order in second-harmonic wavelength, realigned the output second-harmonic beams. Computer simulations predict that adjustment of a single prism can compensate angular misalignment of any or all the prisms before the crystal, and similarly for the prisms after the crystal. We demonstrated such compensation with the experimental device. The simulations also indicate that the phase-matching wavelength band can be shifted and optimized for different crystal lengths.

  3. Sufficient conditions for the avoidance of spectral dispersion in optical prisms.

    PubMed

    Lin, Psang Dain

    2016-07-01

    Prisms are common optical elements consisting of only flat boundary surfaces. Two conditions need to be fulfilled to avoid chromatic aberration for a prism, namely, no mutual image tilt and no mutual image shift for different wavelengths. Mutual image tilt occurs when the unit directional vector of the exit ray varies as a function of the prism's refractive index, resulting in spectral dispersion. In a previous study by the present group [Appl. Opt.45, 3951 (2006)APOPAI0003-693510.1364/AO.45.003951], it was shown that when the rays enter and exit a prism perpendicularly, image reorientation is achieved without spectral dispersion. The present study derives a further sufficient condition to avoid spectral dispersion caused by refraction. The condition explains the ability of Dove prisms and solid glass corner cubes to produce the required image orientation even when the entrance and exit rays are not normal to the respective boundary surfaces. In general, the proposed condition provides a useful analytical guideline for avoiding spectral dispersion in a wide variety of optical systems.

  4. Spatial effects of shifting prisms on properties of posterior parietal cortex neurons.

    PubMed

    Karkhanis, Anushree N; Heider, Barbara; Silva, Fabian Muñoz; Siegel, Ralph M

    2014-08-15

    The posterior parietal cortex contains neurons that respond to visual stimulation and motor behaviour. The objective of the current study was to test short-term adaptation in neurons in macaque area 7a and the dorsal prelunate during visually guided reaching using Fresnel prisms that displaced the visual field. The visual perturbation shifted the eye position and created a mismatch between perceived and actual reach location. Two non-human primates were trained to reach to visual targets before, during and after prism exposure while fixating the reach target in different locations. They were required to reach to the physical location of the reach target and not the perceived, displaced location. While behavioural adaptation to the prisms occurred within a few trials, the majority of neurons responded to the distortion either with substantial changes in spatial eye position tuning or changes in overall firing rate. These changes persisted even after prism removal. The spatial changes were not correlated with the direction of induced prism shift. The transformation of gain fields between conditions was estimated by calculating the translation and rotation in Euler angles. Rotations and translations of the horizontal and vertical spatial components occurred in a systematic manner for the population of neurons suggesting that the posterior parietal cortex retains a constant representation of the visual field remapping between experimental conditions.

  5. Digital Beam Steering Device Based on Decoupled Birefringent Prism Deflector and Polarization Rotator

    NASA Technical Reports Server (NTRS)

    Pishnyak, Oleg; Kreminska, Lyubov; Laventovich, Oleg D.; Pouch, John J.; Miranda, Felix A.; Winker, Bruce K.

    2004-01-01

    We describe digital beam deflectors (DBDs) based on liquid crystals. Each stage of the device comprises a polarization rotator and a birefringent prism deflector. The birefringent prism deflects the beam by an angle that depends on polarization of the incident beam. The prism can be made of the uniaxial smectic A (SmA) liquid crystal (LC) or a solid crystal such as yttrium orthovanadate (YVO4). SmA prisms have high birefringence and can be constructed in a variety of shapes, including single prisms and prismatic blazed gratings of different angles and profiles. We address the challenges of uniform alignment of SmA, such as elimination of focal conic domains. Rotation of linear polarization is achieved by an electrically switched twisted nematic (TN) cell. A DBD composed of N rotator-deflector pairs steers the beam into 2(sup N) directions. As an example, we describe a four-stage DBD deflecting normally incident laser beam within the range of +/- 56 mrad with 8 mrad steps. Redirection of the beam is achieved by switching the TN cells.

  6. Beyond the Sensorimotor Plasticity: Cognitive Expansion of Prism Adaptation in Healthy Individuals

    PubMed Central

    Michel, Carine

    2016-01-01

    Sensorimotor plasticity allows us to maintain an efficient motor behavior in reaction to environmental changes. One of the classical models for the study of sensorimotor plasticity is prism adaptation. It consists of pointing to visual targets while wearing prismatic lenses that shift the visual field laterally. The conditions of the development of the plasticity and the sensorimotor after-effects have been extensively studied for more than a century. However, the interest taken in this phenomenon was considerably increased since the demonstration of neglect rehabilitation following prism adaptation by Rossetti et al. (1998). Mirror effects, i.e., simulation of neglect in healthy individuals, were observed for the first time by Colent et al. (2000). The present review focuses on the expansion of prism adaptation to cognitive functions in healthy individuals during the last 15 years. Cognitive after-effects have been shown in numerous tasks even in those that are not intrinsically spatial in nature. Altogether, these results suggest the existence of a strong link between low-level sensorimotor plasticity and high-level cognitive functions and raise important questions about the mechanisms involved in producing unexpected cognitive effects following prism adaptation. Implications for the functional mechanisms and neuroanatomical network of prism adaptation are discussed to explain how sensorimotor plasticity may affect cognitive processes. PMID:26779088

  7. Prism adaptation in Parkinson disease: comparing reaching to walking and freezers to non-freezers

    PubMed Central

    Nemanich, Samuel T.

    2015-01-01

    Visuomotor adaptation to gaze-shifting prism glasses requires recalibration of the relationship between sensory input and motor output. Healthy individuals flexibly adapt movement patterns to many external perturbations; however, individuals with cerebellar damage do not adapt movements to the same extent. People with Parkinson disease (PD) adapt normally, but exhibit reduced after-effects, which are negative movement errors following the removal of the prism glasses and are indicative of true spatial realignment. Walking is particularly affected in PD, and many individuals experience freezing of gait (FOG), an episodic interruption in walking, that is thought to have a distinct pathophysiology. Here, we examined how individuals with PD with (PD + FOG) and without (PD − FOG) FOG, along with healthy older adults, adapted both reaching and walking patterns to prism glasses. Participants completed a visually guided reaching and walking task with and without rightward-shifting prism glasses. All groups adapted at similar rates during reaching and during walking. However, overall walking adaptation rates were slower compared to reaching rates. The PD − FOG group showed smaller after-effects, particularly during walking, compared to PD + FOG, independent of adaptation magnitude. While FOG did not appear to affect characteristics of prism adaptation, these results support the idea that the distinct neural processes governing visuomotor adaptation and storage are differentially affected by basal ganglia dysfunction in PD. PMID:25976516

  8. Analytical models for the groundwater tidal prism and associated benthic water flux

    USGS Publications Warehouse

    King, Jeffrey N.; Mehta, Ashish J.; Dean, Robert G.

    2010-01-01

    The groundwater tidal prism is defined as the volume of water that inundates a porous medium, forced by one tidal oscillation in surface water. The pressure gradient that generates the prism acts on the subterranean estuary. Analytical models for the groundwater tidal prism and associated benthic flux are presented. The prism and flux are shown to be directly proportional to porosity, tidal amplitude, and the length of the groundwater wave; flux is inversely proportional to tidal period. The duration of discharge flux exceeds the duration of recharge flux over one tidal period; and discharge flux continues for some time following low tide. Models compare favorably with laboratory observations and are applied to a South Atlantic Bight study area, where tide generates an 11-m3 groundwater tidal prism per m of shoreline, and drives 81 m3 s −1 to the study area, which describes 23% of an observational estimate. In a marine water body, the discharge component of any oscillatory benthic water flux is submarine groundwater discharge. Benthic flux transports constituents between groundwater and surface water, and is a process by which pollutant loading and saltwater intrusion may occur in coastal areas.

  9. Chagas disease as a cause of heart failure and ventricular arrhythmias in patients long removed from endemic areas: an emerging problem in Europe.

    PubMed

    Vannucchi, Vieri; Tomberli, Benedetta; Zammarchi, Lorenzo; Fornaro, Alessandra; Castelli, Gabriele; Pieralli, Filippo; Berni, Andrea; Yacoub, Sophie; Bartoloni, Alessandro; Olivotto, Iacopo

    2015-12-01

    Chagas disease is a parasitic disease caused by the protozoan Trypanosoma cruzi. In endemic areas (South and Central America), Chagas disease represents a relevant public health issue, and is the most frequent cause of cardiomyopathy. In nonendemic areas, such as Europe, Chagas disease represents an emerging problem following the establishment of sizeable communities from Brazil and Bolivia. Chagas cardiomyopathy represents the most frequent and serious complication of chronic Chagas disease, affecting about 20-30% of patients, potentially leading to heart failure, arrhythmias, thromboembolism, stroke and sudden death. Because late complications of Chagas disease may develop several years or even decades after the acute infection, it may be extremely challenging to reach the correct diagnosis in patients long removed from the countries of origin. We report two examples of Chagas cardiomyopathy in South American women permanently residing in Italy for more than 20 years, presenting with cardiac manifestations ranging from left ventricular dysfunction and heart failure to isolated ventricular arrhythmias. The present review emphasizes that Chagas disease should be considered as a potential diagnosis in patients from endemic areas presenting with 'idiopathic' cardiac manifestations, even when long removed from their country of origin, with potential implications for treatment and control of Chagas disease transmission.

  10. From ancient to contemporary molecular eco-epidemiology of Chagas disease in the Americas.

    PubMed

    Guhl, Felipe; Auderheide, Arthur; Ramírez, Juan David

    2014-08-01

    One of the best-studied populations with regard to Chagas disease is from the coastal area of northern Chile at the foot of the western Andean slopes. The extremely arid climate here generates rapid, spontaneous desiccation of buried bodies, arresting the decay process. The absence of rainfall then preserves these dried bodies (mummies) for millennia. The aim of the present study was to perform the first molecular paleoepidemiological study on a set of 43 mummified human remains from the Atacama Desert in Northern Chile in order to elucidate the transmission dynamics and determinants of ancient genotypes, to try to unravel the natural history of the Trypanosoma cruzi taxon and Chagas disease. Interestingly, TcBat, a recently described Discrete Taxonomic Unit, emerges as the plausible ancestor of T. cruzi. The findings herein presented allow us to present a plausible model of T. cruzi transmission in pre-Columbian civilisations. PMID:24675555

  11. Radionuclide evaluation of left-ventricular function in chronic Chagas' cardiomyopathy

    SciTech Connect

    Arreaza, N.; Puigbo, J.J.; Acquatella, H. Casal, H.; Giordano, H.; Valecillos, R.; Mendoza, I.; Perez, J.F.; Hirschhaut, E.; Combellas, I.

    1983-07-01

    Left-ventricular ejection fraction (LVEF) and abnormalities of regional wall motion (WMA) were studied by means of radionuclide ventriculography in 41 patients prospectively diagnosed as having chronic Chagas' disease. Thirteen patients were asymptomatic (ASY), 16 were arrhythmic (ARR), and 12 had congestive heart failure (CHF). Mean LVEF was normal in ASY but markedly depressed in CHF. Regional WMAs were minimal in ASY and their severity increased in ARR. Most CHFs (75%) had diffuse hypokinesia of the left ventricle. Seven patients had a distinct apical aneurysm. Correlation between radionuclide and contrast ventriculography data was good in 17 patients. Selective coronary arteriography showed normal arteries in all patients. Therefore, chronic Chagas' heart disease joins ischemic heart disease as a cause of regional WMA.

  12. Sperm Morphological Features Associated with Chronic Chagas Disease in the Semen of Experimentally Infected Dogs

    PubMed Central

    Rodríguez-Morales, Olivia; Pedro-Martínez, Elvia; Hernández-Pichardo, José Ernesto; Alejandre-Aguilar, Ricardo; Aranda-Fraustro, Alberto; Graullera-Rivera, Verónica; Arce-Fonseca, Minerva

    2014-01-01

    The presence of trypanosomatids in the reproductive systems of different mammals (causing genital lesions in the acute stage of the disease) may predispose the animals to low semen quality. However, there are no studies examining the alterations in the sperm morphological features in the chronic stage of Trypanosoma cruzi infection. Knowledge of these aspects is important to understand the other ways of transmission of the Chagas disease. Progressive motility, mass motility, concentration, and sperm morphology of 84 ejaculates of dogs that were chronically infected with T. cruzi were evaluated. Most of the findings were consistent with the reference values and with those obtained from healthy control dogs. The scrotal circumference was not correlated with spermatozoa concentration in the infected animals. In conclusion, the T. cruzi Ninoa (MHOM/MX/1994/Ninoa) strain does not cause significant alterations in the semen quality of dogs experiencing chronic Chagas disease (at concentrations of 5 × 104 to 1 × 106 parasites per animal). PMID:25114010

  13. [The contribution of Carlos Chagas Filho to the institutionalization of scientific research in Brazilian universities].

    PubMed

    Almeida, Darcy Fontoura de

    2012-06-01

    This paper studies the period considered the 'prehistory' of the Instituto de Biofísica, namely between November 1937 and October 1945, during which Carlos Chagas Filho championed the inclusion of scientific research at Universidade do Brasil (UB), despite facing multiple and complex obstacles. The lack of successful precedents at UB isolated him to one inexpressive chair. The equipment available was inadequate for his purposes; there were no official sources and forms of access to funding for science or trained personnel for research activities. On the other hand, Chagas Filho won over allies due both to the political and social clout of his name and his marriage, and to his scientific influence ensuing from his success in attaining the goals he fought for.

  14. Population genetic structure of Meccus longipennis (Hemiptera, Reduviidae, Triatominae), vector of Chagas disease in West Mexico.

    PubMed

    Brenière, Simone Frédérique; Waleckx, Etienne; Magallón-Gastélum, Ezequiel; Bosseno, Marie-France; Hardy, Xavier; Ndo, Cyrille; Lozano-Kasten, Felipe; Barnabé, Christian; Kengne, Pierre

    2012-03-01

    The originally wild species of the Meccus complex are important vectors of Chagas disease in Mexico. In West Mexico, Meccus longipennis plays an important epidemiological role. To understand the genetic structure of the domestic and wild populations of this species, a preliminary study with five polymorphic microsatellite loci was conducted. The population genetics analysis showed high structuring between peridomestic biotopes, with breeding subunits detected in a single peridomestic structure. In the wild environment, two genetic patterns were observed according to the biotope, possible breeding subunits in large rocky formations and a larger panmictic unit in agropastoral areas, suggesting considerable dispersal of bugs in this biotope. Moreover, the discovery of two foci of wild populations at the edge of Guadalajara city raises the question of new urban areas where the phenomenon of bug incursions into households could constitute a risk of transmission of Chagas disease.

  15. Interferon-γ and other inflammatory mediators in cardiomyocyte signaling during Chagas disease cardiomyopathy

    PubMed Central

    Ferreira, Ludmila Rodrigues Pinto; Frade, Amanda Farage; Baron, Monique Andrade; Navarro, Isabela Cunha; Kalil, Jorge; Chevillard, Christophe; Cunha-Neto, Edecio

    2014-01-01

    Chagas disease cardiomyopathy (CCC), the main consequence of Trypanosoma cruzi (T.cruzi) infection, is an inflammatory cardiomyopathy that develops in up to 30% of infected individuals. The heart inflammation in CCC patients is characterized by a Th1 T cell-rich myocarditis with increased production of interferon (IFN)-γ, produced by the CCC myocardial infiltrate and detected at high levels in the periphery. IFN-γ has a central role in the cardiomyocyte signaling during both acute and chronic phases of T.cruzi infection. In this review, we have chosen to focus in its pleiotropic mode of action during CCC, which may ultimately be the strongest driver towards pathological remodeling and heart failure. We describe here the antiparasitic protective and pathogenic dual role of IFN-γ in Chagas disease. PMID:25228957

  16. [Carlos Chagas Filho: an articulator of the history of sciences in Brazil].

    PubMed

    Domingues, Heloisa Maria Bertol

    2012-06-01

    A letter sent in 1982 by a group of scientists to the president of Conselho Nacional de Desenvolvimento Científico e Tecnológico appealed for a policy of preservation of Brazilian scientific culture. The name of Carlos Chagas Filho topped the list of signatures thereby proving his commitment to that proposal, the ideological structure of which was part of his experience in scientific policy in Brazil and abroad. This document harks back to the practice of the history of the sciences in Brazil and the creation of places for the safeguard and organization of scientific memory, such as the Museu de Astronomia e Ciências Afins, Casa de Oswaldo Cruz and the Sociedade Brasileira de História da Ciência, of which Carlos Chagas Filho was an inaugural member of the board of directors.

  17. New approach towards the synthesis of selenosemicarbazones, useful compounds for Chagas' disease.

    PubMed

    Pizzo, Chiara; Faral-Tello, Paula; Yaluff, Gloria; Serna, Elva; Torres, Susana; Vera, Ninfa; Saiz, Cecilia; Robello, Carlos; Mahler, Graciela

    2016-02-15

    Herein, we describe a new approach towards the synthesis of selenosemicarbazones. The reaction involves an O-Se exchange of semicarbazones using Ishihara reagent. Eleven selenosemicarbazones were prepared using this methodology, with low to moderate yields. Among the prepared compounds the m-bromo phenyl methyl derivative 1b was selected to be evaluated in vivo, in a murine model of acute Chagas' disease. Compound 1b 10 mg/kg bw/day reduced 50% of parasitaemia profile compared with the control group, but was less effective than Benznidazole (50 mg/kg bw/day reduced 90%) and toxic. These studies are important to guide future Chagas drug design. PMID:26774036

  18. Diversity-Oriented Synthesis Yields a New Drug Lead for Treatment of Chagas Disease

    PubMed Central

    2013-01-01

    A phenotypic high-throughput screen using ∼100,000 compounds prepared using Diversity-Oriented Synthesis yielded stereoisomeric compounds with nanomolar growth-inhibition activity against the parasite Trypanosoma cruzi, the etiological agent of Chagas disease. After evaluating stereochemical dependence on solubility, plasma protein binding and microsomal stability, the SSS analogue (5) was chosen for structure–activity relationship studies. The p-phenoxy benzyl group appended to the secondary amine could be replaced with halobenzyl groups without loss in potency. The exocyclic primary alcohol is not needed for activity but the isonicotinamide substructure is required for activity. Most importantly, these compounds are trypanocidal and hence are attractive as drug leads for both acute and chronic stages of Chagas disease. Analogue (5) was nominated as the molecular libraries probe ML341 and is available through the Molecular Libraries Probe Production Centers Network. PMID:24900788

  19. [Carlos Chagas Filho: an articulator of the history of sciences in Brazil].

    PubMed

    Domingues, Heloisa Maria Bertol

    2012-06-01

    A letter sent in 1982 by a group of scientists to the president of Conselho Nacional de Desenvolvimento Científico e Tecnológico appealed for a policy of preservation of Brazilian scientific culture. The name of Carlos Chagas Filho topped the list of signatures thereby proving his commitment to that proposal, the ideological structure of which was part of his experience in scientific policy in Brazil and abroad. This document harks back to the practice of the history of the sciences in Brazil and the creation of places for the safeguard and organization of scientific memory, such as the Museu de Astronomia e Ciências Afins, Casa de Oswaldo Cruz and the Sociedade Brasileira de História da Ciência, of which Carlos Chagas Filho was an inaugural member of the board of directors. PMID:22473448

  20. Flip-chip assembly of VCSELs to silicon grating couplers via laser fabricated SU8 prisms.

    PubMed

    Kaur, K S; Subramanian, A Z; Cardile, P; Verplancke, R; Van Kerrebrouck, J; Spiga, S; Meyer, R; Bauwelinck, J; Baets, R; Van Steenberge, G

    2015-11-01

    This article presents the flip-chip bonding of vertical-cavity surface-emitting lasers (VCSELs) to silicon grating couplers (GCs) via SU8 prisms. The SU8 prisms are defined on top of the GCs using non-uniform laser ablation process. The prisms enable perfectly vertical coupling from the bonded VCSELs to the GCs. The VCSELs are flip-chip bonded on top of the silicon GCs employing the laser-induced forward transfer (LIFT)-assisted thermocompression technique. An excess loss of < 1 dB at 1.55 µm measured from the bonded assemblies is reported in this paper. The results of high speed transmission experiments performed on the bonded assemblies with clear eye openings up to 20 Gb/s are also presented. PMID:26561097